
Things You'll Need
.* These are also sold as water absorbing crystals, crystal mud, crystal soil... You get the idea.

Instructions
~Cut the fabric into a rectangle 45 inches long and 4 1/2 inches wide.
~Fold the fabric in half, so you have a doubled-over section of fabric 45 inches long and 2 1/4 inches wide.
~Fold the fabric in half, so you have a doubled-over section of fabric 45 inches long and 2 1/4 inches wide.
~Sew along the long side of the tube to secure the fabric into a tube shape.
Tips & Warnings
- Soak your collar in cold water for three minutes to reactivate it.Lay your collar out to dry at room temperature after use.The collar can also be used for heating by microwaving for a short period until warm.Heat times will vary by microwave. Caution when you microwave this item!!!!!!!!
http://www.brighthub.com/environment/green-living/articles/120758.aspx
Read more: How to Make a Cool Collar | eHow http://www.ehow.com/how_8691066_make-cool-collar.html#ixzz2WVQiCz2q