As for the canned air, I have had two dealers use it to clear out my Bernina. The first time she just barely sprayed it in and said if your very sparing it's OK. The second lady sprayed from behind the machine, pointing the nozzle at an angle toward the front of the machine. I was surprised at how much lint came flying out because she had already brushed the bobbin case area well and I thought it was clean.
I also have a small vacuum cleaner with an tiny hose and attachment for cleaning it. In fact, I need to do that before I start stitching today. Thanks for the reminder!
Glad you got your "problem" solved, even if it wasn't really a problem.

That was my 1st thought too. When I had a gammill,it was notorious for scaring the wits out of me...right before the bobbin thread ran out!