You know what the quilting wisdom is: if you cut with your rotary cutter and it leaves those pesky threads attached.....it's time for a new blade.....whether the blade is relatively new or not! My group of friends laugh because a few years ago we all went in and bought a large quantity of blades and split the order up....I think, I paid for 25....but we're all so frugal, that we're cutting and complaining about the uncut threads instead of just changing the stupid dull blade!