circa Tue, 8 Jun 2004 16:42:33 -0400, in rec.pets.cats.health+behav,
Joe Carmichael (ncmstrjo@sympatico.ca) said,

Try sheets of newspaper or tinfoil to start.

Laura

A squirt of water from a spray bottle followed by a loud "NO!"

Put some pennies in a can and shake them. Most annoying sound but can be
effective.

Anything that makes her not want to be up there even if you aren't in
the room. Otherwise she'll just go up there when you aren't around.
Tinfoil (aluminum foil) was mentioned and is a good idea. If she's one
of the rare ones that doesn't mind foil, get a mat, like for your
kitchen sink, that has those hard rubber beads on the back, then put it
on the table with the rubber beads facing up.
In case it needs to be said, don't put anything interesting up on that
table for awhile. The less she's entertained by being up there, the less
she'll want to be.
If you have a cat tree or climbing post, put that near the table so she
can still be up high to see out the window, assuming there is a window
near the table.

If you catch her on the table, remove her with a 'no' and put her where
you'd prefer her to be. On the floor, on her cat tree, whereever. Then
praise her for being on the preferred surface.