Kerosene works well. The neatest trick I learned in the service to clean a nasty weapon prior to inspection was to disassemble it, pack it full of GoJo or Goop (the non-pumice kind - very important!), and let the parts sit overnight. After sitting, scrub everything with a brush and rinse in hot water - as hot as you can stand. Let the parts air dry from the warmed metal and then lube and re-assemble. I still clean my rimfires this way when they get really crapped out.
I suspect those hand cleaners are really just jellied-up kerosene.
I suspect those hand cleaners are really just jellied-up kerosene.