Mounted up an old window air conditioning unit and its performance was poor. When I looked at the heat exchanger I could see why. There was an almost total blockage by a mat of some hairy fungus stuff. Since I had to take it apart to clean it I thought it would be best to take photos of the chassis for future reference. The waste heat exchanger was by far the more dirty of the two heat exchangers.
This video shows the construction of a table that is finished using a vinegar with steel wool reacted and dissolved into it.