Perhaps only vaguely relevant to cap badges, but this might shed some light on how plastic items get broken:
Sometime late 1959/early 1960 we were issued with FN C1s with experimental woodwork made of a plastic material that replaced the traditional wood. The plastic was dull, and of course, to the disappointment of the old school CSM, could not be polished with linseed oil like regular wood. Guess what? The CSM ordered us to break the stocks. He didn't want to see any of the plastic stuff survive the trials. Needless to say, the plastic was busted into smithereens. Wonder how far that set us back until the M-16 with its plastic woodwork came along?