When this happened (frequently) in the dealers we used to leave the part in the parts cleaning bath with the fluid running over it and use just the blade from the craftsman type knife very carefully, for the really stubourn ones i had an air powered scraper from "Snap on" but thats a bit pricey if you aint using it a lot! As to the honing you dont need to go to the expense of a hone over here we have "glaze busters" which are like what is known as a Flap wheel(lots of pieces of abrasive emery cloth) with a long spindle and this will remove any rust and glaze. The expensive and not easy to get part is the rings, it may be cheaper to get a 555cc kit for a 500 from ebay as that is 2nd oversize 550 (0.5mm) and bore to suit