I used Simple Green...it got the stuff clean but it sure isn't as good as safety solvent or K2.  It will discolor aluminum if left to soak too long.  I finally got rid of my parts-washer and went back to my old drain pan and solvent for the few parts I need to scrub.

BB

I have used Simple Green, Dawn, and 409. I too have heard the horror stories about Purple Power (thankfully without the chemical burn lesson). Ultimately I was dissatisfied with the “soaps” and went back to the five gallon cans of low vapor pressure solvent from Tractor Supply. It evaporates much slower than kerosine. The Tractor Supply solvent will remove the paint from a HF parts washer.

Has anyone ever tried using a kitchen dishwasher with some of that super cleaner stuff in it?

I've got two parts washers, one in my home shop and one in the shop across town. Both are in buildings that I do not heat 24 - 7. So they get the stuff Hornman mentioned from TSC. I have tried all the stuff mentioned that is soluable in water, but have not found it to be acceptable mostly because of time it takes and difficulty in getting the part dry. My favorite parts washed is one I made by slicing a 55 gallon drum in half longwise. I am using a 5 gallon metal bucket under it as a sump and a power steering pump from a mid 70s Ford heavy duty truck to move the fluid. The pump is an Eaton Geroller design that has proven to be excellent. (I worked at the Hydraulics division of Eaton at their Proving Grounds at the time). I have a full flow filter in the circuit so the fluid is always devoid of particles. It is great for flushing out coolers and engine blocks because it is a positive deplacement pump and will put out plenty of pressure. I am thinking of converting my other one to the steering pump design.

As said earlier Simple Green (emulsifier) and the similar products dulls' the paint pretty good if you let it sit. I've found what works best for me on cars and airplane engines ( when installed) is to first pressure spray it down with mineral spirits then pressure spray it with the emulsifier (Simple Green) right away then hose it off with a lot of water right away. Simple Green (and their competitors) is really caustic to me when pressure spraying it but petrolium solvents don't clean off the dirt just the oils. The Simple Green is the emulsifier that  breaks down the solvent and removes the dirt. When cleaning parts in a parts cleaner I do it the same way and if I need to I use carb cleaner first then solvent then the simple green then water but there still might be scrubbing involved. Some times if it it bad enough I have had to use aircraft paint stripper or oven cleaner. All these products except oven cleaner are available at the car parts stores.