Backstory:

I am a DM to 4 players in a partly home brewed partly book based campaign. Most recently the players had to acquire a permanent address and when they didn’t have enough money for a down payment they decided to rob a casino. 

I generally try not to railroad my characters despite the fact that they had ignored many offered work arounds. So I worked hard on it and I built a riverboat casino with some cool items in the vault for them to steal (1, for the story, 1 for coolness, and 1 to sell). In the vault I also put a large amount of gold. The gold however I made clear was cursed so that it would cause severe burns on anyone that touched it. I know my 4 players and I knew they didn’t have anything to really work with this and so I hoped they would move on from the idea and potentially try and steal other things or just work on the sealable items in the vault  

Here’s the issue. We had a last min player join us for just this 1 session and he had several things built into his character that made it possible for them to steal a lot of this cursed gold. They now have a lot of it but not a lot of idea what to do with it. They (for now) have buried it on a remote sand spit but are actively in the city looking for solutions to the issue so they can use the gold. 

I have temporarily distracted them with a quest but I know they’ll want to get back to searching for some way to remove this curse so they can get a large amount of money to buy I don’t even know. 

does anyone have any advice?? I feel bad just telling them there’s no cure to the curse but also that amount of gold would be low key game breaking. 

The 2024 DMG has a "Bastion" system, a preview of which you can find in the Unearthed Arcana.

You said they stole the money to buy property, right? The rest of the money could be used to expand and furnish it. The Bastion system has lots of different rooms which cost a shitload of money for a rather minor (but still cool) buff. It's a great money sink that feels mechanically useful without being overpowered. 

First off, don't worry too much about players having too much gold. I opened my campaign with my players fighting a dragon, and they got a lot of the horde before plot came and swept it away from them. Money is only a problem if you have previously established the world as being "if you have money, you will be able to buy all this powerful stuff and break the game". Even if they do use the money to buy powerful things, you can rebalance, as long as they all stay fairly level in power (which you can enforce, as the DM, by only offering items for sale which will keep them roughly aligned).

More important considerations are:

• what ramifications will come from robbing the casino? Very few rich people are safe to cross, so as soon as they start spending, they will start attracting attention, and then they will be targeted for revenge.
• What ramifications come from you giving them a whole pile of tiny magic items which burn people who touch them? Will they use them as ammo? traps? will they fill up a bag of holding with them and then empty it if they are swallowed by the tarrasque? The curse on the coins is possible more problematic than the monetary value.
• How broad is the curse? If this is right after the event and you haven't established too much, you might reveal to them that it is them that are cursed for taking the gold, rather than the gold becoming a weapon - and any valuable precious metal they touch now burns them. The silver locket of your loved one? the earrings you're wearing? Your platimun holy symbol & arcane focus? All burning.
• Who owned the casino? Powerful wizard? Polymorphed dragon? Powerful mob-boss? lvl 20 cleric to the draconic god of greed?
• Would the casino have a means to magically track their gold? If so, they might have an ambush waiting for them when they get back.

If you haven't defined the amount of gold exactly then work out the cost of this property they want and make the two fairly close - leave them some reasonable change, but make it an amount you don't consider game-breaking.

The curse pretty much makes the gold useless.  When they try to spend it and it burns the seller no one will take their gold.  

The nice thing about cursed items is that Remove Curse explicitly doesn't work on them (it'll break attunement where relevant but won't remove the curse on the object itself). Typically breaking a curse on an object (or huge pile of objects) is a matter of a quest. So, come up with a couple of good curse-breaking options that would all require quests to bring about.

Maybe there's rumored to be a super secret curse-breaking spell that requires an ultra rare component that you can only get by *quest*. Maybe the curse can't be lifted until the mage who cast it dies, and wouldn't you know it, they've gone and become a Lich; to destroy them, you'll need to *quest*. Maybe the curse can't be broken without a specific item used in its casting, which was last seen at *quest*. Maybe the curse was part of a deal with Mammon, Demon Lord of Greed, and to break it you'll need to go find him and *quest*. There's options here, is what I'm saying. This will also give you time to figure out what you're going to do if your players suddenly become trillionaires overnight; how do you tell a story with characters for whom money is never an object? It's very possible to do. Start by answering this question: What in this world is important that money absolutely cannot buy?

If you're afraid this unexpected occurrence will become the focus of the campaign... Welcome to running D&D! It's never not like this! But by giving your players a quest centered on an objective they set for themselves, you can be assured they'll be motivated and engaged. If you had a different campaign in mind that you had already heavily planned for, you can probably tie it in to the cursed gold one way or another. Think about the NPCs and organizations you've prepped: could any of them be involved in the curse-breaking quest line? Or, if you can't swing that... That's also D&D, and this is why most experienced GMs will tell you "Don't Prep Plots".

Basically; don't think of the gold as game breaking, think of it as game changing. Running tabletop games is often about accepting a lack of control, and this is a strong object lesson in that. It's going to be okay. It won't be exactly what you expected, but it is going to be okay.

Tax

there's this wonderful invention called "stealing"

It's D&D. You have a lot of options.

The casino could track the curse magic and send people (and keep sending people over and over) to get it back. Maybe don't do something as cruel as the party comes back to an empty pit, but have someone laying in wait to ambush them when they do try to dig it up. The party has essentially created their own villain who is going to keep going after them until they get that money back. Or the casino could press the party into service and after enough missions remove the curse and call it square.

Or, lean into the quest aspect and send them on an adventure to get it un-cursed by a suitably powerful NPC. Or provide them with a suitably powerful NPC (or two or three) who wants spicy gold for some weird reason and who is willing to trade a favor in kind. Maybe some goofy wizard wants to make a golden golem that burns to the touch. Or a red (or gold) dragon thinks they would be ideal nesting material to keep their eggs warm on. They could essentially launder the gold for the party, giving them a smaller amount of "clean" gold back in return. Or they could give the party a "break glass in case of emergency" way to summon help in a dire situation.

Ok a few points:

• If you want to simply take the gold away from the players then TALK to the players about it. If you just have a monster attack and steal it or a criminal organization come in and steal it most likely result is the PC swear to hunt them down and take it back. As they will see it as a new story hook not as you trying to fix a mistake. So if you want to just take it away from them explain your reasoning and if they are good players they will listen and allow you to make it go away with whatever narrative reasoning you like.
• Gold is only as useful as you make it in your world. Ask the players what their characters want to do with the gold once it is uncursed and discuss with them what is/isn't reasonable to use it for - most of the time they won't actually use it to break the game, instead they horde it like Scrooge McDuck, so it is fine to allow them to have it. If becoming wealthy nobles with a mansion/keep and personal guards/servants is too much for their current level then simply design the "cure" to the curse to be so difficult that they need to be of an appropriate level to have a mansion in order to remove the curse - e.g. having the curse be caused by a high CR devil or hag, or having the curse originate in a land very far away from where they currently are (since it was a river boat casino after all) and them have to journey out there to remove it.

You could use it as a hook into a whole different direction for the campaign if you want to, or keep it as an interesting side plot for a later date.

Options: use encumbrance rules.  Gold is heavy, after all, which limits how much they can reasonably carry out without access to bags of holding.  Another option: limit how much gold is actually in the vault at the time of the heist.  Maybe the casino has just shipped a large amount of money off to another location.  Maybe the vault that the PCs know about isn't actually the main vault.  Maybe the casino is having money issues and most of the coins are actually fake- lead coins wrapped in gold leaf, for example.  They still can steal some gold, just not as much as they thought they'd be able to.

After X amount of time away from the casino, the curse teleports the gold back.

Or

The curse allows the owners of the casino to identify the location/people who stole it.

Quote from Jademoonrabbit >>

Backstory:

I am a DM to 4 players in a partly home brewed partly book based campaign. Most recently the players had to acquire a permanent address and when they didn’t have enough money for a down payment they decided to rob a casino. 

I generally try not to railroad my characters despite the fact that they had ignored many offered work arounds. So I worked hard on it and I built a riverboat casino with some cool items in the vault for them to steal (1, for the story, 1 for coolness, and 1 to sell). In the vault I also put a large amount of gold. The gold however I made clear was cursed so that it would cause severe burns on anyone that touched it. I know my 4 players and I knew they didn’t have anything to really work with this and so I hoped they would move on from the idea and potentially try and steal other things or just work on the sealable items in the vault  

Here’s the issue. We had a last min player join us for just this 1 session and he had several things built into his character that made it possible for them to steal a lot of this cursed gold. They now have a lot of it but not a lot of idea what to do with it. They (for now) have buried it on a remote sand spit but are actively in the city looking for solutions to the issue so they can use the gold. 

I have temporarily distracted them with a quest but I know they’ll want to get back to searching for some way to remove this curse so they can get a large amount of money to buy I don’t even know. 

does anyone have any advice?? I feel bad just telling them there’s no cure to the curse but also that amount of gold would be low key game breaking. 

 What was the actual quantity of gold?

Dispelling the curse reveals the truth that this 'gold' is really iron with gold leaf wrapping, and the curse was there to prevent people from being able to properly inspect it.

If the local ruler hears that the characters have a lot of gold then they are going to request some "taxes" or "war contributions" or "civil project donations" or similar.

Now the playes have to decide what to do. Get on the ruler's bad side by not giving in to the extortion requests for help? Get on the ruler's other bad side by giving them cursed gold? Something else?

I would use the money as ammunition =)

One thing I have to emphasize: if you let the players rob the casino, don't just take away all the treasure.  That's a jerk move: at that point you might as well have not let them pull the heist in the first place.  They've got to be allowed to come away with some sort of reward.  Also, if the party would only be able to steal the gold because of one new character's special abilities, do they even know that?  Because if not, I'd just go ahead and change how the gold is protected to negate that ability and give them the option to come back later (or find somewhere else to rob- generally having a robbery means that people have less faith in a location's ability to protect its valuables so they store less there in the future).

Quote from 6thLyranGuard >>

One thing I have to emphasize: if you let the players rob the casino, don't just take away all the treasure.  That's a jerk move: at that point you might as well have not let them pull the heist in the first place.  They've got to be allowed to come away with some sort of reward.  Also, if the party would only be able to steal the gold because of one new character's special abilities, do they even know that?  Because if not, I'd just go ahead and change how the gold is protected to negate that ability and give them the option to come back later (or find somewhere else to rob- generally having a robbery means that people have less faith in a location's ability to protect its valuables so they store less there in the future).

 That's a really great point, actually.

If the gold was taken from a dragon, or something like that, just make the gold cursed. If not, put some super expensive prize right under their noses, then make that cursed (or not, if the prize is useful to the story.) 

I think there are many mundane or exotic ways to solve this problem and it is hardly insurmountable. 

The easiest is to make the price of the next item they want very high.  I use this all the time.  Other pedestrian ideas are tax, bulding permits, payment for titles, transporting valuable and heavy items through a dangerous magical world, the gold is in turn stolen from them, etc.

Exotic ideas as mentioned above work fine as well.  The gold turns to dust, teleports back to the casino, allows bounty hunters to track it down, etc.  

I have some great advice for the players. Melt gold into weapons. 

Also kinda works for you as it is something to do with the gold.