boiling works for me
i can easily peel off the tire from tamiya and speedmind rims (im not sure how other brands of rims would react to boiling
) ive also removed old foam donuts from 1/12 rims using this method. its very easy and only minimal cleanup.
i tried acetone for my offroad rims and it also works, but i prefer boiling. i suggest that you first test one method on a practice rim to see which one is easiest and safest