GRRR! I HATE it when these kind of things happen! I'm glad you got it fixed!!!
I have a machine that gives me problems with three threads coming up out of the bobbin area and that stops the fabric from feeding. It ends up messing up the fabric and usually tearing a hole if I don't catch it in time. I had this machine torn apart. I mean, I had every screw out that would come out. All the platic cover was off...Yes, I did manage to get it all back together, but my hubby had to "fix" something for me that I didn't do or didn't do the right way. I have cleaned this machine beyond clean! The last time I tried it out, it sewed for an entire 6 inches. I turned it off and left it. I haven't touched it since. This was my back-up machine....bad choice for a back-up. I have since gotten a different back-up, but, you know, it did the same darn thing!?!~ I really gave it a good cleaning, and it seemed fine after that.
I have used the sweeper on my machines. I have not used the canned air, but I have heard really good things about it.
I have a paintbrush that I keep in my sewing supplies that I used to brush out the bobbin area and everywhere it will reach down there in the lower part of the machine. It really gets a lot of lint and fuzz stuck to it because it has gotten machine oil on it, which makes the fuzz stick better.