And of course AFTER it's already in the oven baking I see not to use surfaces you use for food. Why can't you? Did I just ruin our cookie sheet for anything other than baking clay on or is it still okay if you wash it really well? Nowhere gives a specific reason other than that kitchen stuff and crafting stuff should be separate (which if I had stopped to think about it that makes sense, and I would have covered the cookie sheet). Like, is it toxic or...? I'm kind of freaking out because my mom was just saying how she loves this specific cookie sheet because it was a total steal we've had for 20+ years (it's stainless steel and she got it for $1), and I don't want to have to tell her I was stupid and I ruined it.