This is actually sort of a system. Starting with new files or you
can recondition old ones. Use a piece of copper sheet (20g or 24g
shaped like a U. Run it against the file with directions of the
teeth. The copper will conform to the teeth and make a counter rake.
After the file is clean, dip it in some none oil base cutting fluid
from a machine shop supply. It should only be slightly wet, not
dripping when you file the material. During the filing process it
easy to clean the file with a soft brush. (Copper or Bristle) If the
file loads again and it can if it dries out. You just start all over
again with the copper U.
Alpine Custom Jewellers & Repair