http://www.rcuniverse.com/forum/m_93...anchor/tm.htm#

I did find that not rinsing a part will cause it to darken over time. I cleaned, without rinsing at all, a crankcase over a year ago. It's been sitting and has darkened a bit. I usually rinse in hot water and the parts are excellent.

As Pe suggests, steel parts need immediate rust prevention. They will rust in minutes right before your eyes after a US bath. I use motor oil dissolved in kerosene.