Cleaning burnt-on grease with ammonia I recently ran into this (put your pans etc in a closed container {a garbage bag will do}, pour in a bit of household ammonia and let it sit for many hours) and love it.  However, I also have some pans with those black plastic? handles, is it safe to do on them also?  I also have a teflon pan that has some grease stuck on the outside.  Since there's no way to treat only the outside {it's the fumes that do the work, you don't immerse things} is that safe?
After asking this in multiple places and finding nobody with an answer I decided to test with the gunkiest cover.  The handle came through fine.  I'm not going to try the teflon pan.