[Harp-L] How often should I clean my harmonica?

[Bob Marsolais]

I'm a newbie to the harmonica and I tend to slobber a lot into my harp 
while I practice.  I tap my harp on my knee several times after each 
use, but I'm sure its not pristine after tapping.  My 4 harps are either 
Lee Oskar or Seydels  and have plastic combs. How often should I clean 
them.  I'm thinking of getting an ultrasonic cleaner to minimize risk to 
the reeds, but what liquid should I use?  Any thoughts would be appreciated.

Thanks, Bob