The file should always be angled and not parallel.
At an 88-degree angle, you now move along the edge of the entire ski in a working direction marked with an arrow on each file, using small, even strokes. Always grind from the beginning of the ski to the end. Any residue left during grinding is cleaned with a microfiber cloth.
A grinding burr has formed that needs to be removed. To do this, use the grinding rubber or a diamond again. Place the grinding rubber parallel to the base surface and pull it from front to back. If you have a diamond, moisten it and do the same.