Many videos on YouTube showing that copper grease is apply on brake calipers and back of brake pads. Isn't grease is slippery when rain flow the grease to the brake pads and rotor?

 

I use Permatex Brake Lube. Never a problem with it getting anywhere it shouldn't. Just apply a small amount to the back of the pads and where the metal backing contacts the spring clip.

 

Remember that a little bit goes a long way ... and with all brake work "Cleanliness is next to Godliness"