What a surprise! When I was winding a bobbing, it broke and kind of jammed my winder, too! It was a pain to remove all the thread off the winder, but I did it with patience.
Come to think of it, this bobbin could have been as old as 30 years old... I kind of thought the clear plastic was yellowing a bit.
So, I learned my lesson.
If a clear plastic bobbin looks slightly yellow, it's time to thank it and say good bye to it. I kind of wish they kept on using the metal kind for all new plastic sewing machines, too. Oh well.