Simple Green and Chains
There has been some discussion at Velonews Tech letters about prolonged soaking in simple green and the potential for it to eat away at chains.
I use SRAM chains or at least a Sram quick link on shimano chain for just this very purpose. Easily taking it off for a cleanup in Simple Green.
A rep from Simple Green replied to Leonard Zinn's article and mentioned a new product that was designed for the aircraft industry that would work well on bicycle parts:
Extreme Simple Green
I've been known to forget about a chain soaking in Simple green for weeks. It was rusty when I took it out. I will remember to be better about doing that and might try to get a hold of some of this new stuff.