Did they leave a black residue or did they actually scratch the floor? If it's just a residue, there are several things you have around the house that might work. First, try rubbing a little WD-40 on them. Be sure to clean the area to remove the WD-40 afterwards as it can be very slippery.This might wipe them right away. If that doesn't work, let me know and I can suggest a few other things to try.