Unfortunately it's quite easily done. I say unfortunately because it can easily be a very time consuming procedure. It's called Retouching, and it can been done in Photoshop and various other programs as well. However, depending on the version of Photoshop there might now be better and less time consuming procedures. As always, the best approach is to eliminate as much dust etc. as possible before shooting the PhotoCopy, which of course is not a scan. Proper preparation can shave many minutes of working time, as is the case with most projects.