Comstar 90-099 Coil King Professional Grade Concentrated Alkaline External Condenser Coil Cleaner, 1 Quart Bottle, Yellow

Used this product with a 1 gallon garden sprayer to clean 3 Lennox ACs. Removed fan and applied to both sides of coil. There is foam at 3:1, but it is not as much as the small cans. Nonetheless, it worked perfectly, pushing out contaminants. Beware that there is a smell within the first 5 minutes, it will dissipate. Cleaned both sides with water and the coils are now clean. Used 1.75 bottles for 3 units.

So after a day of wheeling in the mud...I use the this the next day to clean radiator....spray on and it literally pushes the grime right out of the fins. Stuff works amazingggg just don’t get any on ya as it burns like heck. As far as scent it smells terrible...weird question to ask...but that normally means it’s working...

This is very powerful cleaner! It took the paint off the condenser on my air conditioning unit. I diluted it approx 1:3 (1 part cleaner to 3 parts water), it could probably have been diluted to 1:6. I would also advise you make sure you wear long sleeves, gloves, and eye/face protection when using this.

I mixed it 3 to 1 which is what the instructions directed, but I didn't think it was that strong of a solution. Better than plain water or soap but I did get it on me some and it didn't even burn. The ingredient is lye, which as you know, oven cleaner also uses lye as the main ingredient, but that stuff will burn your skin quick. I am going to try to find an acidic version next time. My outside condenser is about 15 years old and on its last leg. Needs all the help it can get.

It works well for the price, just don't dilute it more than three times.

This product deep cleaned the condenser coils on my heat pump. I used it at full strength on the inside and outside of the coils and the foaming action did the job. My HVAC functions more efficiently now.

Hands down the best coil clear that I have ever used as an non-professional. Diluted 50% and aplyed with a garden pump sprayer. You could smell the crud cooking off. Wear gloves and rinse well. Better than any cleaner in a spray can.

Some stuff claims alot. This actually does alot.