Y'all probably know this, but...a microwave works by "exciting" water molecules. That's why it's so easy to boil water or reheat food, but they don't retain their heat like they would if you put them in the oven instead.
If you put a model kit in the microwave, chances are it might explode. There are little airpockets in the pieces sometimes, certainly in the sprue, and any "loose" molecules in there could get "over excited" and cause a..."bad" shall we say? reaction.
Lay the pieces out on a paper towel overnight and have patience.