Found this in an old (1996) Home Brew Digest #2183.
I can confess to ignoring the occasional moth and fruit fly but these guys have the right attitude …

Genius comes into play when the you realize an accident is actually a
major discovery. Such as with Maine Ale and Lager Tasters president
Brews Stevens’ lambic. Brews brewed up a 15 gallon batch of cloudy
wheat beer and put it into three five gallon buckets in the basement
of his vintage home. The joists are carefully hung with spider webs
duplicating Leifman’s brewery in Belgium. He left the covers off and
allowed chance to do the wild thing with his brew. After three weeks,
he discarded one bucket with brown scum on it while the other two held
a healthy looking white fuzz.

A bunch of us were sipping the result (an outstanding cassis lambic)
as Brews related this tale. At bottling time, Brews noticed an area of
gray fuzz in the head of one of the buckets. So, he scooped out what
he thought was a minor area of mold. It turned out to be a field
mouse. Brews said, “He had a smile on his face, though!” We all
laughed and said it was too bad that the batch was ruined. “Ruined!”,
exclaimed Brews. “I put ten pounds of black currants to it!”

After a moment of silence…we looked down at our glasses…. looked
at Brews…Naw….Yeah!! Someone, I don’t remember who, passed
‘Mouseketeer Cassis Lambic’ through his nose. I hadn’t seen that trick
since Ronnie Farr shot milk out his nose after watching Mundo Gorgis
eat his own ear wax in second grade.

We all watched and took another sip. Hmm. None of that typical rodent
after taste. More silence. “You know what living organisms do when
they die?”, asked Dr. Tom, our club physician. “They void their bowels
and bladder.” We looked at our glasses….looked at Dr. Tom…looked
at Brews…took another sip. Hmm. None of that typical rodent-after
after taste.