I'm tm not picking on you but accumulate what's been commented in several posts..
I had experience in the chemical and cleaning industry...
Acidic cleaners are the wrong pH for dirt and are going to do nothing but possibly activate or worsen rust.
Purple Power as far as the cleaner itself is very high on the alkalinity scale because it has sodium hydroxide... This is also known as caustic soda. It's effective but if it's used enough it will eat off paint finishes and attack metals. purple Power sells a wash and wax product that is economical and one of the better washing wax products I've ever used for your exterior paint finish.
Simple Green is probably one of the best cleaners ever put on the market for repeated use...what will make simple green work the best is to put it on and give it 20 or 30 minutes to work.
Heat always makes a difference in the cleaning process...even a scrub brush dipped in hot water will clean far better than one in cold water.
A water hose hooked up to a hot water spigot is amazing.
Heat and agitation are your two biggest factors in cleaning... Pressure is a two-headed sword ... It can get bad things out of nooks and crannies and it can get good things out like Grease.
Also any cleaner needs to be rinsed thoroughly.. Some cleaners will attack bushings, gaskets and o-rings.
Also taking the vehicle for a good drive before you put it in a garage is a good idea if you want to keep ahead on the battle against corrosion.