What I am finding curious is all of the people saying that stripping models is a hassle. If that's the case you might be doing something wrong. Admittedly I only strip metal minis...but that's literally two steps: 1) Set in ultrasonic with a cleaning solvent of your choice....2) brush off.
Before (eBay):
After...:
Plastics can be done with...what, denatured alcohol or something similar. I don't bother with plastics because I don't trust that people assembled them correctly. As far as metals go, they're extremely easy to restore back to original metal with very little effort.