I've used bore butter as a patch lube but I've never been inclined to use it as a rust preservative or anything like that... and I've heard some horrific stories about "seasoning".
All that being said.... you can eat it I'm told, so you could maybe spread it on a sandwich if yer hungry... or lettuce leaves or whatever should the need overwhelm you ...
I use a wad over powder before I put the ball down, so when hunting the patch lube doesn't contaminate the powder, and I'm not convinced you could contaminate it enough anyway to matter.
Aloha...
