Clean Copies For Class

I photographed a worksheet on my desk and the students' pencil marks and smudges show across the page. I need to know whether this is salvageable by cleaning the scan—remove pencil smudges, erase stray marks, keep printed lines and tiny clip art crisp—or whether I should retype parts instead because the scan will look uneven when printed. Tell me the least risky sequence to try first, something I can do in the next 30 minutes and stop before I lose the printed texture, and give one clear test (print at 50% on plain paper) that will tell me if I must re-create the page instead.