I am a huge simple green advocate for stripping paint from minis. It works safely on metal and plastics in addition to being biodegradable. Something interesting occured. I stripped some warriors of harad which were spray primed with gw undercoat. Black, or whatever its called. The simple green will not remove the primer. All the other color has been brushed away, but the primer remains. This really isn't an issue since I was going to modify the minis then reprime them, I just thought I would pass on this information to the community. Perhaps this is an answer to the age old question, what's the difference between paint and primer? The answer is, simple green won't strip real primer.