The yarn I use is from second-hand stores and is usually less than a full ball.

Cylinda Mathews’ pattern was free online some decades ago - before Ravelry. The old website is long gone, and it’s not yet added to her new one: http://www.crochetmemories.com/

Periodically, I make a few and pass them out to anyone who’s interested. They’re a great break from huge, seemingly never-ending projects, and give nearly instant gratification.

2011-05-14 At the moment, it’s just a kit of small balls of cotton worsted weight yarn, hook, directions, and discarded CDs. It’s ready to go.
2014-05-15 photos added of a couple of the coasters - given to knitting buddy, Ginette, last year.
2014-09-16 Since it had just come out of the laundry, I decided to add a scan of a black one I’d made some time ago. This is the first time one was overlooked as I transferred laundry from washer to dryer, so it’s the first time one was dried in the dryer instead of stretched wet onto its CD and allowed to air dry. I was surprised that I was able to stretch it while dry and get it onto its CD! However, it’s more easily done wet. Next time, it’ll get its own lingerie bag!

I love how the shiny CDs show through between the ‘spokes’!

It’s about time to make some more, and I’ll try to remember to do them with an adjustable center. I’d like to be able to snug up the hole a tad, just so it fits down inside the CD’s hole. But … maybe then it wouldn’t fit the outside? Time for experimentation!