hands down by far the BEST paint stripper i have EVER used was this stuff i got at wal-mart called "super clean" (might have been "purple clean" its been a while since i striped anything)
this stuff will just rip appart the paint, while leaving your models (metal or plastic) in perfect shape.
one time, i threw about 20 kroot models in a mid sized tub full of this stuff to strip. well, i forgot about them, and i belive a something like 2 months past by. i went to a tourny, an ddicided i wanted to field my kroot again. so i looked and looked but never found them. that is untill a day or so later while i was cleaning out that room the tub was in.
i had the lid sealed on so not much evaproatied. but i just put on some rubber gloves, got my old strpping toothbrush. and started brushing the paint off. they were then painted in sir lanka by
http://www.paintedfigs.com/
just fill a small tub (somehting that is large enough to hold all the minis) with this stuff.
for plastic models, 3-4 days of sitting is fine. i let em go for a week if need be just cus im lazy
for metal models, they are ready to strip in LESS THEN 24 HOURS.... amazing but true. i once tosed 3 old tau metal stealth suits in the tub before heading off to work. came home, striped, re based, and re primed them and started painting them again.
be sure to throughly wash the models with water after you finishing tooth brushign all the paint off.
also, the tooth brush will start to get sope bubble build up all around it and the model. avoid rinsing that bubbly crap off in the stripping tub if at all posible.
an important note... if the model was glued together poorly, then the glue has a very good chance of breaking appart. BUT i used testors model cement on those 20 kroot and they were fine. even after that 2 months.
another important note. i have not tried this on anything from forge world.