The short answer is kind of makes it brand new. I know some barber hones original packaging recommended rubbing in some Vaseline every few months with the palm of your hand. I have found that especially after lapping (as Butzy says above a topic of no little debate) it seems to re hydrate and smooth them out. On that lapping point - it is definitely no fun and I don't disagree with the school of thought says if it doesn't absolutely need lapping leave well enough alone, but of the dozens and dozens (I really need to make a list) of BHs I have lapped and re hydrated the only problems I have run into have been with a couple of Sears Craftsman hones that were already pretty far gone. By which I mean starting to get that white chalky appearance that indicates it may be too late the binder is going.