Marco Leon wrote:
"Ross" wrote in message
...
I was told it is the balled up lead deposits in the spark plugs that needs
to be cleaned out while servicing them. This by a 50+ year A&P.

Perhaps I heard from a more contemporary source.

http://dictionary.reference.com/browse/dingleberry


n. Vulgar Slang

1. A piece of dried feces caught in the hair around the anus.
2. An incompetent, foolish, or stupid person.


So basically MX?