I'm a firm believer that if you are diligent at maintaining your sewing machine at home you will not have to spend a fortune getting your machine serviced...which the last time I heard was about $75! Ouch!
All it takes is a little time at home to clean your machine, change the needle, and oil it if your sewing machine manual instructs you to do so.
To clean your bobbin case all you will need is a pipe cleaner...you know, the wire, fuzzy pipe cleaners that kids make cute things out of in school.
Fold the pipe cleaner in half to form a loop.
Gently use the pipe cleaner to go inside your machine and then pull pipe cleaner out, do this a few times covering as much of the inside of the machine as you can without hurting any of the inside parts. You will be amazed at how much lint a pipe cleaner will pull out.
I do this every time I put in a new bobbin...which is pretty often, and look how much lint I get out every time.
If lint is left inside your machine it can do major damage. I encourage you to do this little ritual every time you change your bobbin and your machine will be happy for a long time to come.
Oh, and remember...CHANGE YOUR NEEDLE OFTEN. This too will make a huge difference in your sewing machine's performance.
So get cleaning...happy sewing!