If you are just pulling and checking them, it doesn't hurt to give them a quick cleaning b4 putting them back..brake cleaner works well, so does gasoline if in a pinch. I used to clean them instead of replacing them when I was McDonald's broke..
Here goes..,
I totaled my '95 Lexus SC400 3 months ago (entire rear end destroyed)
it has a V8 which ran smooth as glass, still does but is not drivable.
I owned it outright & I didn't have full coverage so now I'm eating it.
I bought an '89 Camaro RS to drive for now, perfect interior...