Had a call for a Scotsman machine in the back room of a restaurant. It was filthy! Asked the woman in charge when the last cleaning was performed. Her answer was every couple of months they cleaned it. Startup date was 1997. Asked her who didi the cleaning, and she said she did it. When I asked her how she cleaned she said she turned the control board from freeze to clean and let it run for a half hour, then turned it back to freeze. Hmmm.