Last week I placed thirteen plastic Warriors of Rohan from Games Workshop's Lord of the Rings line of 25mm miniatures into a small glass jar and filled it with just enough Simple Green All-Purpose Cleaner so that they were covered. The purpose of this was to see how good the product was at stripping paint from plastic miniatures. Here's a photo of the miniatures prior to getting the Simple Green treatment.
With a little gentle scrubbing from an old toothbrush I would estimate that a good 95% of the paint was removed. Here's a photo of the miniatures after the scrubbing.
One thing I was aware of is that the plastic miniatures are more fragile than their metal counterparts. The LOTR range in particular are modelled quite realistically and this means thinner weapons than normal Games Workshop 'heroic scale' 28mm miniatures. Because of this I tried hard not to be too rough with the toothbrush. Even so, I did manage to break off half of a spear. Ah well, that can be easily repaired.
Overall, I'm very happy with the Simple Green results. It's also safer and nicer smelling than other types of products that can be used to strip paint. I'll definitely be using this product for all future miniature paint-stripping projects.