I use a Butner on mine when they start to get too thick with cake. No problems yet. It's nice to refresh the smoothness of the wall to allow easier loading and easier drop down as the baccy burns.
I recently ordered my first cob and it should arrive tomorrow. I'm heading to Tahiti in a few weeks and thought it might be a good beater pipe for the trip. Needless to say I'm looking forward to trying one after hearing about them for years.