It means I have removed all the lint from every area I can get to. On my vintage it also includes oiling. Huge difference in what I can "get to" to clean between my vintage and my newer machine. Very frustrating that I can not do as complete cleaning as I would like on the newer... its all sealed up . I just know there is more lint but can't access the underside of the machine . I guess with the newer machine the manufactures want the revenue from forcing you to bring the machine in for a real cleaning.