If there is no contamination by oil or grease, sliding surfaces should only be cleaned dry if possible. Cleaning with residue-free agents such as acetone, alcohols or grease-dissolving agents (e.g. Loctite 7063) is also permissible if lubricants adhere to the bearing. If cleaning agents have been used on bearings with a running-in film (dg22 and dg26) and the running-in film subsequently shows signs of damage, they can be reworked using bonded coating sprays (recommendations on request).
Mating materials can be cleaned with acetone, alcohols or other degreasing agents. The cleaner itself must be residue-free.