For patient self-care of carpal tunnel syndrome, ice and "contrast baths" of the arms is recommended. What is a contrast bath?

More or less: Put your arms in the warm/hot bath for 3 minutes and then move to the cool/cold water for 30 seconds. Repeat this cycle 3 times. Always ending in the cool/cold water. A bath where you alternate hot and cold water. This does not require the submersion of one's whole body, just the arm and wrist, so use of a bucket or sink is fine.