Your third option is a Jet spray vs Power washing options. Instead of using detergent, use a jet spray option hot chemical solution and heat to release the parts of all residues, at the same time as power washing also uses hot chemical solution with an additional hydraulic power. If you are looking for anew with a very low consumption of detergent, then power wash would be the best solution. Less detergent and chemical solution not only saves water, but time, as there is no call for for a long wash cycle. Now next time somebody asks you "What is industrial Parts Washers?", you can definitely show off a little bit of your brain!