On Tue, 28 Jul 2009 13:18:31 -0700 (PDT), Frank
wrote:


I was recalling time neighbor had ducks and they were cute but crapped
all over our driveway.
Eventually disappeared with time. I think there is a similarity
because birds swallow rocks to grind food in thier crop and it
probably comes out as inorganic debris needing mechanical removal or
washing.


This is the OP. I tried vinegar. It works. I found ordinary
laundry bleach works even better.

Thanks for all the interest.

Duke