Originally Posted by oatw13
I have also tried them and they do seem to help if you are having bobbin problems. I have only used them on the front loading bobbin machines, not the top loading bobbins, although I am sure it would work on those, also.
One package should last forever unless you lose them all. They are pretty durable.
Yes, they do work, I have a top loading bobbin and it works fine there as well. The only birdnesting I've encountered was over where a lot of seams converged, and that wasn't a bobbin issue so much as a fabric-moving issue.
These also make great gifts to people with new machines!