You might take a look at this thread:
http://www.audiokarma.org/forums/sho...d.php?t=140210
I cleaned that chassis in the bathtub with some spray cleaner and then hosed it off with the shower.
You have to use a little discretion and keep water away from the flyback and power transformer, also paper labels should be covered or temporarily removed first.
Most late 50's sets used plastic coil forms and molded caps so they are pretty water resistant.