Black basing and hairspray chipping

Yeah that's a tough one. I love black baseing and do it on everything now including ships, What I've done for chipping is black base, then spray aluminium where I want to chip, then use AK Interactives Worn Effects because it can be brushed on.
Spray the silver on lightly so the basing still works. It seems to work well enough.

I'm sure others have a better answer.