I have always used unwaxed dental floss. I run it through 6 or 8 times to be sure I have gotten every bit of shredded thread bits. Never ever use canned air as Sandy says. It can make the problem worse. You can use a tiny attachment for your vacuum cleaner to try to gently suck out any bits you can't reach. Don't be afraid to bring it in to your tech. They can reach areas we can't. BTW, you can buy those little attachment kits at most dealers. I sure hope you can get this fixed son so you can stitch again.
Air spray (canned air) is not recommended for bobbin area as it blows junk up into machine. Try running a folded piece if fabric fold down thru upper part of your tension, muslin is good and I use it.
SQ
Or unwaxed dental floss. I am sure you changed the needle. When ever thread shreds in my machine it is the needle.