Also worth noting. In the same way that it will destroy lacquer finishes on wood stocks, and damage synthetic polymers, it will also quickly remove the finishes on many alloy and steel guns. If the finish was a baked-on (essentially paint) type, the brake cleaner will strip it, fast.

There is a well-know thread on a Beretta forum with exactly that happening on a modern Inox (stainless) Beretta 92FS. The frames on those Inox models are anodized aluminum, but they are then also finished with a rather suspect silver-ish paint. One guy used brake cleaner on the frame, and it bubbled-up all the silver paint.