I had my wood floors removed from my kitchen and new tile laid. Unfortunately, there is mastic residue on the wood floors remaining in my family room. They are Bruce hardwoods a about 12 years old. How can I clean them?

Try Goof Off or Jasco adhesive remover. Try it in a hidden area. Valspar® Goof-Off (http://www.goof-off.com/val/resident/goof-off.jsp)