I am looking for experienced opinions for agents to clean indoor coils in HVAC units. I have used foaming cleaners on window units in the past and that is my starting point.

I plan to do routine cleaning of the indoor coils of my mini splits. So far, I have used what I can find on the shelves of nearby stores. That would be spray cans of foaming AC-Safe and Frost King. The latter has been less expensive, but the former can be sprayed with the can upside down. Both contain "metasilicate" which appears to make it alkaline (perhaps as a substitute for now difficult to find TSP). For some of my units clearance for the part of the coil next to the wall is difficult.

Though I found the foaming nature of these attractive, maybe I would be just as well off with dilute dish detergent in a tank sprayer and save a lot of coin. I rinse them with a tank sprayer now anyway.

I'd appreciate your suggestions.