I had my brother 1500d serviced the other week and the repairman showed me how to undo the case to clean it if I've been doing something that creates a lot of lint. He also sold me a can of air because he said it will do a lot less harm than having lint stuck in places we can't see. But never ever blow into the machine with your mouth. He also made the comment about people using cheap thread and cheap needles. If you've paid good money for a machine why would you jeopardise it with cheap thread and needles. Made sense to me.