I've used simple green for cleaning chains but apparently it's not good for them because of corrosion issues (high sodium content or something to that effect).
I soaked a chain in it over night and it came out with corrosion marks. I was surprised since I've done this to several chains and this was the first time it happened. There are pictures of chain plates cracked at the pins, which I can only assume is caused from corrosion around the pin effectively increasing the pin diameter.
Try mineral spirits, it's about the same price and works just as well in my limited experience.