I have been on my back under the SF260 trying to wash the black grime off of the plane. I can use 409 detergent forever and even with much rubbing can only get a little of the grime off. Varsol is mineral spirits and this worked much better but still required scrubbing with a rag.

Now I am using Varsol, $4.00 a gallon 4/5 parts
Gunk Concentrate, $16.00 a gallon 1/5 part

For the really hard grim, soil that has been in place for a year or more, it still requires using a rag with the VARSOL and GUNK mixture but for most of it I can simply spray the Varsol/Gunk mixture on using a pump up pressure garden sprayer, [they cost $28.00] and then washing it off with the hose. I do not know where to buy an atomizer. That is what we used to use before the FBO moved off and took it with him. The atomizer used the shop air hose and would blast the bottom of the plane with Varsol.

I tried using a high pressure washer and it did not seem to be any better than just using city water pressure.

any suggestions?