A hydrocollator reaches internal temperatures that are hot enough to kill living organisms and bacteria. This makes the machine itself and whatever goes inside of sterile. If you wish to clean your hydrocollator, make sure it has fully cooled and is not plugged in. You may use water and vinegar to wash the inside of the machine. Be sure to pat dry and reconnect the machine. Once it reheats again, it will sterilize itself once the internal temperature reaches 160° F.