I pick up a couple sets of coarse and fine Lansky 'Dog Bones' every year at Blade and either have them stashed all over the place or give them to a needy knife user. You have to wash them occasionally though, no big deal.
Mhawg, how do you wash them? I assume you're trying to remove imbedded metal from previous use.
I've found this method to be good:
1. Make a paste of "Cameo Aluminum and Stainless Steel Cleaner" ( get it your local grocery next to the "Comet" ...see
http://www.greatcleaners.com/cameo-fm.html ).
2. Butter up a folded, moistened paper towel with the cameo-paste and scrub the ceramic rod.
3. Rinse with warm water.
Cameo works better than Comet,detergent,etc 'cause it contains sulfamic acid
which makes short work of all those 'metal marks' in the ceramic.
It won't hurt the ceramic. (see
http://en.wikipedia.org/wiki/Sulfamic_acid).
Cameo is also great for cleaning up the glass coffeepot ( do this at least once per decade...

) as it also cuts the oily residue left by 24,000 pots of coffee.
JMH
(Chemist by education, Engineer by vocation, now retired...)