Brake fluid is magnificent for removing paint from any kind of model.
I buy a lot of cheap, pre-painted minis off E-bay and I have a sealed tupperware container with a few bottles of brake fluid in it. I just dump the minis in, wait a week (only a few hours is really necessary though) and when I take them out the paint practically falls off. Use an old toothbrush or a Dremel tool with a rotary brush bit on the end. Safe for all metals and plastic, available anywhere: it's the standard type of brake fluid you put in cars everywhere.
I usuallly run them under warm water in a sink and rub the paint off. Make sure you put a screen over the drain or you will lose small pieces! It also weakens superglue a lot.
BE SAFE: It is toxic! Follow all the warnings on the packaging labels!
Oh, to the confused folks in the UK: Simple Green is a type of universal/floor cleaner.