When filing soft metals, like aluminum, brass, copper, etc., load the file with chalk first, it helps to prevent the soft metal from loading up in the file. Keep applying chalk as it wears away. After I am finished, I just use the brush side of the file card to remove the residual chalk and they are clear of any metal. I have found that when working with 304/304L, 316/316L and 18-8 that chalk works okay but crayons do a better job.
Some years back I decided to finally invest in some "good" files. I now use Pferd files and what a difference a fine tool makes. It is a pleasure to work with them.
