I use fume free Easy Off oven cleaner available in most supermarkets and discount department stores like Wal-Mart, K-Mart, etc.
I get the larger size zip lock freezer bags (1 quart size?), put the kit inside and liberally spray it with the Easy Off. Normally I disassemble the kit as much as possible removing the turret, tracks, road wheels (if possible) and any little loose parts.
I let the model and bag sit overnight, usually in our downstairs bathroom sink, but you could put it in a mop bucket or kitchen sink in case your bag springs a leak. Use an old toothbrush and toothpicks to work the loose paint from cracks like panel lines.
Once it's basically stripped, I wash it thoroughly with dishwashing detergent and let dry.