Yes, the differentiation between damage and filth would seem obvious, but it is a real consideration. Those indicating that there is nothing that can be done about groove damage are correct, no amount of cleaning can reverse careless treatment or scratches. On the other hand, it is amazing how much better an otherwise fine, but dirty, record sounds after cleaning. Sad are the time when one stumbles across a seeming gem, only to clean it up and find there is groove damage.
Funny though, and it may seem heretical to some, but my son was down from college last week and I was playing a couple of old jazz favorites that have a pop or two and some fuzzys between tracks. I apologized that I didnt have a better copy and he said that he often finds that part of the charm of older records and it didnt bother him in the least. A romantic notion, perhaps, but he and I still enjoyed listening VERY much!