I don't! One of the best features of my Juki machines is the auto thread cutter... even on the longarm. The cutters leave about 1/4" tails. I take a look at the back when I'm done and trim those tails down close to the quilt surface. After all the difficult picking I have done, I know those threads are not going to come out on their own. Washing seems to further 'set' them into the quilt.