Have you quilted it all already or do you still have more blocks to do? If you have more blocks - or a tip for future quilting .... start with a loooong top and bottom thread, take one stitch and pull the bobbin thread through to the top then make sure both are out of the way before you start again. Do the same thing when you stop. When your done you can bury these long threads into the batting of the quilt. Yes it takes more time, but it's a good way to have clean starts and stops.