Fingerprint Damage, Business Strike Lincoln & Grading.

What causes finger print damage on say, a 1969 P business strike
( obviously fingers , lol but when would that usually occur?) I am aware
That oils from fingers do commonly damage freshly minted proofs if taken from the capsule, but what about business strikes?

and how many grade points so to speak do they take off after they have been damaged by such?


Fields are still highly reflective, mirror like even
There is a big fingerprint visible in the field above liberty.
And is probably red/brown.