When I bought my new machine, the dealer had a maintenance class that she STRONGLY encourage I take. I did learn a lot. Newer machines need to be cleaned after every 10 hours of sewing. We learned how to take the bobbin area apart, clean and reassemble. This class was invaluable. I am going to take it again (it's free) because when I cleaned my machine this past weekend, I had a few questions pop up.
Never ever use canned air to "blow" your machine. You can easily mess something up with the air pressure. I like to use a vaccum to clean out the bobbin area, but was told the sucking pressure could harm something. They suggested putting a straw in the nozzle attachment to reduce the pressure. They said it would still get any of the lint balls out - which it did. Took me all of 15 minutes from start to finish.
I would strongly suggest that you take a maintenance class and learn to clean your machine properly. Then clean it regularly.
Ok, that's my story.