I never thought to get rid of my bobbins! I have all the bobbins that came with my 80s Singer and ones I added to the stash. I have all the bobbins and those I added to my Baby Locks. I keep some filled for Embroidery (with a black dot on them), the others I fill as I need them. Some of you on this board mentioned using the left overs for piecing and that helped me a lot. I can now say I do have empty ones. I have never used prewound purchased ones.