Originally Posted by Wing42

Exactly what I would have said, except clearer, better organized, and more authoritative.

I worry about the blue cold packs. Our freezer is -10 degrees. A cold pack could be too cold for too long on the skin and could cause frostbite or other tissue damage. In contrast, once ice starts melting, the surface temperature is 32 degrees, not cold enough to cause damage.

Also, once a blue cold pack is warmer than freezing, it continues to warm to the point where it is no longer therapeutic. Water and ice stays at a therapeutic 32 degrees until all the ice is melted.

Another pleasant way to apply cold is to fill a styrofoam coffee cup with water, then freeze it. You can then gently massage the sore area with the ice, holding on to the cup as a comfortable handle. Peel back styrofoam from the top of the cup as the ice melts down. Then chuck the whole thing when finished.