There are so many types of foam and of as many different chemical compositions. Not that this should be taken as standard but the wiki for hot wire cutter has this for the first sentence:
A hot-wire foam cutter is a tool used to cut polystyrene foam and similar materials.
Standard pink crafting foams appear to be made from polystyrene as well. Polystyrene is a really broad plastic and it is used in lots of things though. Standard expanded packing foam (the white bubble stuff) is made from polystyrene. So I should be able to work with any of those?
I keep foam packing materials in case I need to return products. I need a way to identify foams that are safe to use a hot-wire cutter on. I think a smaller list to limit myself to certain foams as supposed to listing which ones I should avoid (assuming there are any?)
Keeping to the actual foam variants: Is that what I should limit myself to? Polystyrene? Some fumes can more toxic than others. Some foams might be more flammable than others.