Scuffing

Ripken

I realize this is sort of a hard question to answer, but what has been your experience with PSA and light scuffing. I don't mean major markings, just the often-found color breakup that occurs in older cards that have very dark backgrounds. This is jusst the product of primitive inks & drying I guess. How does PSA treat a card that would otherwise grade well (sharp corners, good centering, etc)?