For Peggie - Thanks!
 

I recently asked for your advice regarding a stinky head. Turns out the
culprit appears to be the hose and drain from the sink in the head, which is
plumbed to the raw water intake to the toilet. I took your advice and poured
some Raritan CP "Cleans Potties" down the sink with the intake valve closed.
Sucked this thru the head. You don't wanna know what came out....
I then put some more Raritan CP down the sink and left it there for a a few
days. Bingo. Odor is gone.

Thanks for the advice. The Raritan CP seems to be a great product.