Sewing machines require regular maintenance, just like a car. Regular care will lengthen the life of a machine, and bring more hours of sewing enjoyment. On a regular basis, remove the needle and presser foot, needle plate and bobbin case and clean out the lint within the hook area (this is the bobbin case (opening). Apply oil according to the manufacturer's instructions. A good practice is to do this after the use of 3 complete bobbins or the completion of any lengthy project. Flannel provides lots of extra lint, so take extra care after projects done in this type of fabric. Never blow on the working parts of your machine or use compressed air. This can force the dust further into the working parts of the machine.
After the use of 3 bobbins, it is a great time to replace the existing needle with a new one. Needles dull after extended use.