I know the manual for the 6004 says to clean periodically, but how often do you actually do it? I've got about 40 frames on my 6004. I bought it VERY lightly used and took apart the clamps. Cleaned the base and ran towel with isopropyl between the gripper but haven't done anything since. The only thing I notice lateley is that the clamp bases are not as smooth on the used to be, but otherwise no muss.