If you check out my web page you can find a half dozen articles on removing paint. I have more info on removing paint than putting paint onto models! Most of it applies to miniatures, but they will work on models as well. Although I am not 100% sure about removing enamel paint. However the worst that could happen would be the paint doesn't come off.
Castrol super clean is the best. However I am not sure it is still called by that name. Last time I bought some it was "Purple Power" or something. Just look for a giant purple bottle of concentrated cleaner. A 3 day soak will remove even years old paint. If we are talking about a big plastic kit, then perhaps spraying it every few hours and sealing it is a large plastic bag will work.
Simple Green is suppose to work just as well as the purple stuff. Never tried it though since I've had purple juice.
Brake fuild does work, but takes a little longer. The bad part is it's toxic. Also you are not suppose to dump it down the drain. Also be careful using it on resin. It should be fine soaking for a week or so but no more. Many years ago I was soaking a model and got real sick (flu, not from the fuild) and forgot about it for a month. I ended up with a puffy Armorcast Reaver titan.
Over cleaner will work but it is far from my favorite. It stinks, it's messy, and it doesn't work as well as the others.