Last night laying in bed I thought "I'll have to write Margo about easy-to-thread needles for tying off thread after machine quilting" and Bingo! here is the answer--thanks a bunch, Margp--AND kasman for asking the question!

It took a WOMAN to invent that needle! I can't thank Margo enough for sharing that info...I'd never heard of the spiral needle before & I'd bet not many out there have either. For your information, I just ordered mine AND if you order BEFORE July 15th...the shipping is free! These would make great Christmas gifts for those in quilting groups that exchange small gifts. Thanks again !!!

Best to all...Nancygail

Because I always do machine quilting, I don't usually tie off my threads, but use tiny little stitches to secure the beginnings and endings.
Quilters who do machine quilting on show quilts often tie off the threads then bury the thread tails several inches through the batting layer with a regular embroidery needle, or a self-threading needle, or one of the new "spiral-eye" needles. I think those are lots easier to thread, so that is what I use when I knot and bury my thread tails:

http://www.spiraleyeneedles.com/

You might want to watch Sharon Schamber's video about tying off your threads:

http://www.sharonschambernetwork.com/Classes/AllPremiumClasses/Play/TabId/95/SeriesId/108/Free-Area-Tying-And-Hiding-The-Knots.aspx

If you pull the thread to the back and tie it off, the only concern I can think of is that the ends would be buried - pull the knot back into the batting layer - you would feel it snap as the knot is pulled back in. When you pull your needle out and clip the thread, the ends should slip back inside. Definitely would not use nail polish.

I have made a couple of quilts where I had to pull the thread to the back and tie it off. How can I ensure that the knots won't come undone? I thought about using clear nail polish (on a wall hanging that won't be washed frequently). Any better ideas?