Thanks for the heads-up with this thread. I will have to add a steam cleaner as one of the 3 most dangerous things in the hands of a new mechanic. The other 2 are:

1. pressure washer (water) and
2. WD40.

All of these will strip out necessary grease in critical spots such as headsets, wheel bearings, freehubs, brake pivots etc.

The most dangerous thing: is putting a bike on an external car rack, and then driving at highway speeds in the rain. Sure to blow out the grease in every bearing on the bike, even the bottom bracket.

Solution for cleaning a bike... a wet rag. But I spend a lot of time cleaning the outside. Almost all of my maintenance time is spent digging around on the insides.