Best electrical cleaner I have used was called Trich 111. We used while I was in the Navy, it did a great job of cleaning.
1,1,1-TRICHLOROETHANE
I worked on old Model 28 Teletype equipments part of my time in the Navy. When i was in Germany, I ordered a 55 gallon drum of tricholoethane to dip clean the printers from all the excess lubricating oil. I noticed that the solvent made my arms come out white after dipping printers (remove the body oil in my skin from my arms), and the printer soon failed, as the oil impregnated in the oilite clutch shaft bearings was also removed. I was an E-4 with no direct supervision, didn't know better. Most of that 55 gallon drum was still there when I rotated out, Iwonder if they figured a way to dispose of this hazardous waste.
Trichlorethane is a marvelous grease remover, but read the Caig documents to see how their product removes oxides and improves contact conductivity: Oxidation/Contact Resistance test starts on page 7, Caig DeOxIt measurement results last on page 10. Here's a link to the document:
Finally, my best experience with DeOxIt was when I was working as a Medical Center Biomedical Equipment Tech, was called to the surgical pathology lab for a vent blower failure on a tissue processing station. A medical intern or resident works with tissue samples just harvested from an in-process surgery, looks for areas to be examined under the microscope, dissects and frozen micro shaves tissues for the pathologist to do a STAT decision on for the surgeon. The blower was to remove preservative solution and any possible airborne biohazard particles from the area under the hood where the masked and gowned tech was working. The rocker switch wasn't working, I didn't have another switch of the correct size and ratings on hand, and had to fix the switch. Fortunately, the rocker switch had holes in the side near the contacts so that I could get a small swiss file in and file on the contacts. I did that for a few seconds on both sets of contacts, then tried the switch/motor again. It worked 2 out of 10 tries. I then sprayed some DeOxIt in the contact access holes, worked the switch a few times, did one final spray, then set the system up for another test. The system worked 10 out of 10 tries, and got them going again.
I ordered a new switch overnight air and installed it the next day. BTW the blower was a medium sized squirrel cage driven by about a 1/2 hp Dayton motor, so it had a large start-up current surge to satisfy.