I need to make some replacement mirrors for some galvos, they need to be 0.8mm thick; I've had no luck buying 0.8mm thick 1st surface mirros, but I did get a number of mirrors from a polaroid camera and they measure a fraction over 1mm thick; is there any way, without access to specialist equipment, any way of thinning these down? I guess the first thing is to protect the silvered face, the 1st surface mirrors I've bought before come with a blue plastic protective film, something like that would do the job if it can be purchased.