Just found this on a motorcycle website....another peice of info on this subject....be careful...try steam at your own risk! Another vote against steam cleaning. Do bikes have "o-ring" chains?? So after reading this I'm not sure what the LBS that steam cleans does...maybe the just steam clean the frame??

"The high pressures and temperatures created by power washers and steam cleaners will wash the grease right out of a standard chain, which is bad enough, but at least you've got a fighting chance of getting it back in there. However, when those types of washers are used on an O-ring chain, the heat and pressure not only remove the lubricant but can also deform or damage the O-rings. Unfortunately even the best aerosol chain sprays won't be able to force the fresh lubricant past the O-rings (damaged or not), so what you'll be left with is a clean, albeit dry chain that's going to have a very short and unhappy life"