Yep, I melted part of what I think is an ATI brand aftermarket Mosin-Nagant stock.
Gunscrubber bad. It is an effective cleaner, though.
Try brake cleaner, Hoppes spray cleaner, GunScrubber for Synthetics (GunSafe?), etc.
I understand that carb cleaner is bad stuff, I wouldn't want to use it anyway (too much methyl-ethyl-bad-sh*t).
Anyone have any experience using tetrachloroethylene on synthetics? Chlorinated HC are usually bad stuff but it's the solvent in Tetra aerosol products. I've been assuming it's bad stuff for most plastics.
Regardless of what you use, it's a good habit to protect the stocks (even just the way you hold the piece as you clean it, don't let the solvent run all over it) and to wipe it down pretty quickly afterwards.