I've occasionally chalked files, particularly when working with aluminium. The stated wisdom is that it is supposed to reduce clogging of the file teeth.
Coarse files don't clog as easily compared to the finer files, particularly on ali. castings.
I haven't found it particularly effective to prevent clogging, but it does seem to ease cleaning the file (with a piece of flattened copper pipe) afterwards.
Does anyone have any experience with chalked files and whether they can keep the file clean while using it?
This question has come up because I'm working on aluminium castings at the moment.
Dave
The Emerald Isle