Wood Floors

Wood Floors

Hypothetically, let's say you have a friend who is renting a house with old hardwood floors (19th Century, Pine) and the friend has a couple of dogs. And the dogs behave themselves fairly well, but they still have toenails, which leaves scratches in the flooring (or at least the polyurethane coating). What can your friend do - on the cheap, if possible - to deal with the scratches well enough to get back the security deposit?