Cat urine on watercolor painting

A friends cat sprayed urine on a botanical illustration that she is
executing in watercolor.   She has tried to erase the spots off, and
has scraped at them with a razor and tried to cover them with
Chinese white and white gouache all to no avail.  She has even
painted another leaf over the one spot.

Is there anything that can be done to remove these spots from Lana
Hot-pressed watercolor paper?  Is there a way to neutralize this
acid?  I would expect future damage to the painting where these
acidic spots were painted over.

Carol Wickenhiser Schaudt
Botanical and Scientific Illustrator
Nautilus Fine Art Studio
21602 Park York Drive
Katy, TX 77450

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                  Conservation DistList Instance 14:23
                 Distributed: Monday, October 16, 2000
                       Message Id: cdl-14-23-007
                                  ***