The unit that I’ve been cleaning up was donated to us. It looks like nobody ever bothered to clean the unit, just changed the oil. After several tries with the Array/Gordon powdered boil out powdered cleaner, this stuff worked like a charm. Try to get a can even if you have to order one off the net and pay the postage. Once you try it you’ll want to keep several cans around. Amazing stuff, and I’m not easily impressed.