I use the spray silicone on the bed of my sewing machine to keep it slick and the rails on my quilt frame. I have Sewers Aid which is a liquid for the thread. I'm sure the spray would work, too but I use the liquid by letting a few lines run down the cone or spool and letting it soak in for about 30 minutes. It helps control the lint buildup on cotton machine quilting thread and thread does get old & dries out so it helps strengthen it. Coats & Clark machine quilting thread seems to run a lot better with a little help on both my Elna and my Voyager.

I have had cones & spools of thread that were just crap! You could see the uneven-ness in the thickness of the thread and fibers sticking out every which way. One cone of Coats & Clark variegated was ok at first but the middle was terrible! I had to pull off at least 10 yards before it started looking ok again. The really bad stuff you can break easily with your hands. Don't even waste your time with those.

Actually, I was just wondering that - the OP didn't say whether she was machine quilting or hand quilting. If hand quilting, I agree with the Thread Heaven recommendation. If machine quilting, I have a couple of machine-quilting friends that recommend a spray silicone, but I'm sorry to say I don't know what brand. I'm sure others here are more helpful than I!