Lacquer thinners are a blend of sometimes many different solvents, and some blends are "hotter" than others. Here's an example of a lacquer thinner blend...
INGREDIENT(S) CAS Number % (by volume)
TOLUENE 108-88-3 43.0
ACETONE 67-64-1 23.0- 27.0
ALIPHATIC PETROLEUM DISTILLATES 64742-89-8 18.0- 22.0
METHYL ALCOHOL 67-56-1 11.0
ISOBUTYL ISOBUTYRATE 97-85-8 1.0- 3.0
Plastics in general don't holp up to some of these ingredients...especially cleaning brushes with nylon bristles. As said above, most natural bristle brushes will hold up well. If you want something that still cleans well but not quite so hot, you could try Xylol or Toluol (toluol is hotter) or even kerosene. I like Toluol as a good all-around cleaner for parts...does not flash off as quick as most lacquer thinners.