Which ever solution one uses, the real secret is constant agitation, in a case tumbler, back of a pickup, or the best, a vibrating cleaning machine.
ATF, good old tranny fluid:
None of the other products have or will ever have the years and level of research and engineering to remove crud and/or rust, keep spotless, and sustain the life of a $4000+ and higher, piece of high tech equipment; your automatic transmission! It's also the least expensive product.