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1.
The dried-on caked-on grass from the underside of a lawnmower which falls off in muffin-like clumps when starting a mower which has been idle for a day or days. In extreme cases, the mow muffin must be chiseled loose.
The lawnmower scattered mow muffin all over the garage floor when it started.
by Jim Hendricks December 29, 2006