I use a cold pack when I have tired, sore muscles after intense workouts. It works very well. The only issue is that if I'm out of the house, I have to use an instant cold pack which doesn't remain cold for a very long time. A freezable cold pack is best and lasts the longest but a refrigerator is required for that which isn't always possible.
I still keep instant cold packs with me though, because even twenty minutes of cold makes a huge difference for sore muscles.