Ok gang, here we go, this is from Renie moderator of FMS site, worked for a Rheumy for years...
Take a long towel, roll it and put it under the ball of the foot, SLOWLY and GENTLY pull it back toward your body in slow repetitions. Do this as often as you feel comfortable, especially in the morning when this can be at it's worse. By all means go to your Doctor if this is not a help to you.
The towel exercise usually does wonders for me! It isn't working its usual magic in this last go round, though. But I would NEVER quit doing that, as I believe it has headed off a great deal of trouble over the years!
Hmmm, the frozen water bottle sounds intriguing. This is a great idea, too!