Polyester on Cast Iron?
Due to some unfortunate negligence on my part, a tiny amount (just a few small drops) of polyester from a towel ended up melting onto my very hot cast iron skillet. I managed to wipe up the polyester while it was still liquid as far as I can tell, but I'm a little worried that there's still a thin spot/film left on my skillet that's invisible to the naked eye but could still be toxic. Is it still safe to use the skillet, or should I just spend another 20 bucks to buy a new one?
So basically you burned polyester onto your cookware, right? If I am you, then I will probably try to clean it up as much as I can. You may reason the whole pan. You may just get a sandpaper and scrub the heck out of that spot. Or, you may just get a new pan like you said.
<still a thin spot/film left on my skillet that's invisible to the naked eye but could still be toxic.>
The polyester itself at room temperature is not toxic, but its fume is toxic. So you can make it toxic while you are cooking.
I would just use a sandpaper or green pad and just scrub that spot clean, and then re-season that particular spot. If you think this is too much work, then you can just buy a new one for $20 like you said.