If that’s the case, then why do many pad/shoe manufacturers supply small sachets of copper based lubricant with pad/shoe kits. The motor trade in general has been using copper based grease for decades and continue to do so. If there was an issue with this, then surely the public, vehicle manufacturers and various government bodies would object just in case legal vultures got involved. As far as it goes with calliper slide pins, yes, the red grease is the correct one to use.