IAmCatOwned

I just use them up piecing a scrap quilt. I do this several times a year. You can either put the bobbin in your top thread and use it that way or just use a grey thread and use up the bobbins in the bobbin case. I don't ever pull it off the bobbin unless there is only like a yard left. Thread costs a lot. Why waste it? This is also a great way to use up any kind of partial spools.

Yes, I agree, I mostly use shades of grey and taupe for piecing (and black or white when appropriate), but my quilting threads vary. Once I have finished quilting a quilt, I use all the leftover in scrap quilts since I don't usually have enough of any one color to do another full-sized quilt (my most typical size).