1992 silver dollar toning

Hey folks, In the last year I inherited a fairly large collection of coins from my grandfather that him, and my great grandfather started. I've decided to start putting all of my silver eagles into protectors, when I noticed this one coin beginning to tone. I don't know why there are what looks to be scratches on the face, but I was VERY careful handling the coin. I'm not really interested in selling any of this collection, rather I'd love to expand upon it. I'd just like to know what dictates a coins worth after it has been toned, and if I'm doing the coin justice by having it in a protector. Thank you for your time.