My dealer said not to use compressed air since it will blow the fibers deeper into the machine, especially if you have one with electronics (like I do)....not a good idea.
I bought the little vacuum attachment and hook it to a regular vacuum with a hose - works great - makes it look brand new inside.
I also use a folded pipe cleaner to clean around the bobbin area inbetween full cleanings.
When I turned in my old machine for this new one, he said he's never seen such a clean machine. ( I wish my house was this clean :-)