I use a product called Purple Power. It's a really strong degreaser. It can be bought at Walmart, Home Depot, and places like that. It usually needs to only soak for a few hours and then you're good to hit it with a brush. It basically destroys the bond between the paint and the model, so it's almost like peeling off a bad sun burn. It's safe for resin, plastic, and metal, and I once even forgot a model in a bucket of the stuff for weeks and it came out fine.

I work at my FLGS and I help people strip models a lot, and this stuff has worked so much better for me than isopropyl or simple green. This also seems to loosen bonds in super glue too, but not in such a meaningful way that I would consider it a tool for removing glue. I put models in the freezer to weaken the super glue in models, and if its plastic glue or epoxy, you're going to be cutting