Hand and wrist muscle aches and joint pains are often associated with injuries and overuse of these areas. Clinicians that treat the hand and wrist often use warm paraffin wax baths (the same type of wax that is used for candles) to cover the hand and wrist and provide soothing warmth and pain relief.
Warming the muscles and joints of the hand can improve range of motion and decrease pain. Paraffin wax can be very warm and often includes substances like menthol for its soothing properties as well.
IMPORTANT: you should not use a paraffin bath if you have wounds/cuts, problems with feeling hot/cold in your hands, or if you only want to mildly increase the temperature of your hands.