The thread on knives reminded me of a sharpening need I have. I have a pretty nice kitchen knife that I bought a ceramic sharpener for years ago. Its two ceramic round rods which you insert in two round holes so that they are held at about 60 degrees in a V. You draw the knife down vertically about 40 times on each bevel. The rods were white and now seem filled with filings as they are nearly black. Two questions;

1.) How are these cleaned?

2.) Can anyone suggest an alternative sharpener that is not too expensive?