I have a number of pairs of old socks that have one worn hole.Any idea

Use them for dusting. Use them to pack shoes in a suitcase while traveling. Cut the bottoms off and make "cozies" for glasses or cups that are too cold or too hot to hold comfortably.

I just saw a video that used the cuff of a sock as a hair scrunchy.

We have to buy very expensive socks for our cold winters ($20 a pair average). To stretch their use, I learned to darn them. Use a light bulb or tennis ball in the sock in the hole. Knot the thread on a threaded needled and stitch the hole together. I was afraid it would be lumpy and hurt the feet but we cannot tell the darning was done! Use the same color thread as sock and it won't show. If you don't want to save them as socks, use them for making small creatures of them. Here are 62 ideas for you to search: http://www.businessinsider.com/62-things-you-can-do-with-your-old-mismatched-socks-2015-6

I use the leftover socks for cleaning and also polishing. You can also do crafts like making a snowman.

Socks were darned when I was a little girl. I remember those egg shaped wooden things with handles. I think it was a little more involved than pulling edges together, I seem to remember sort of weaving the wool through the sock. I love hand knitted socks!

You could use some fine wool to darn the holes