OK, do your bobbins look like this?
Mine did and I didn't like it, the threads getting tangled and knotted, what a mess!
So I found a solution...
I needed my utility knife
a permanent fine tip pen
and a foot of 5/8" clear tubing (inside measure is 1/2")
I picked the tubing up at my local hardware store.
I marked the tube every 1/4". Then with the utility knife carefully cut the tubing by pushing straight down and gently sawing. It worked best if I squished
the tube together.
Once you have all your "rings" cut, cut it open.
slip the split ring tube over your bobbin and Voila!
Nice, neat bobbins. No more tangles! Yeah!!