I use soap and water on the bike. When I rinse it I am careful not to use the spay stream, but the softer setting.
To clean between the cogs when the chain is off of the bike I fold a cloth rag or paper towel around a thin ruler and rotate the wheel backwards with the rag between the cogs. Works on the front too.
The chain is removed every 750 miles and cleaned in an ultrasonic cleaner. You can use a plastic jar with solvent or SimpleGreen and shake it for a few minutes to get it clean.