Just to rehash the tire mounting theme again...

If you're not fond of working with thinner/acetone (both of which should be handled ONLY when you're wearing protective gloves and in a very well ventilated area), you could always do this:

Sand the rim
Coat both rim and tire in glue, wait to dry
Lightly warm both tire and rim surfaces that have been glued
Wrap wax paper around rim, slide tire on to rim/wax paper, slide wax paper out from between tire and rim

It's been a very very long time since I've done this so I don't remember if it's any easier than the dunking method but I know it's a cleaner, less toxic one