I didn't want to argue but if they fill up quickly that means there is
wood in there and that means they are cutting not burnishing. They do
leave a nice glass like finish. I came across it by accident one day
after using a file to sharpen some things. I had some small branches
that I had cut off on some canes and was out of sand paper so I just
thought I'd try a file and see how it would work. Took em down pretty
good and didn't need any sandpaper. Couldn't get a better finish any
easier than this.