This is for homes w/central air. The condenser part is located outdoors. PIC
The whole outside of the unit is composed of small metal fins to cool down the condensor.
Lowes sells several all-purpose cleaners. i just spray and rinse.
They also sell 20% HCL acid solution to clean metal. The fins are metal. i just pour it along the outside.
the condenser hasnt been cleaned since the house was built (13years).
so all purpose cleaner, or acid solution?