Whetstone and Chalk

Quote from Moxys >>

I understand not adding every mundane item, but removing perfectly proper adventuring items is silly.  It just ends up cluttering the Homebrew with these items which we have to remake in order for our characters or games to feel right to us.

 Well, it's a good thing you can't homebrew mundane items.

Just add a custom item on the sheet or, like I suggested above, include it under Other Possessions if the DM is so unreasonably strict that it can't be considered basic adventuring gear.