For metal traps only (salt corrodes some metals). Mix 1 cup salt with 1 gallon warm water. Pour slowly. Salt lowers freezing point. For Drains Inside Walls (No Direct Access) A. Increase room temperature Open cabinet doors under sink to let warm air circulate. Use space heater in the room. Raise thermostat to 75–80°F for a few hours.
Attaches to metal drain lines, sends current through pipe to warm it. Not for PVC/ABS. Risk of igniting sewer gas — ventilate area first. how to thaw a frozen drain
Aim at the wall where you suspect the freeze. Check for hot spots; don’t overheat drywall. For metal traps only (salt corrodes some metals)