Acetone will break down CA, as will heat. Boiling works fine, but it usually toasts the foam. I haven't tried the oven method, so I can't say on the foams for that. I've seen some gel acetone somewhere before, I will see if I can find it again. Seems to me it was marketed specifically for r/c tire removal, but I could be wrong. Maybe someone else on here knows/remembers what I am talking about,