> Response.Cookies("cookieName").Expires = "July 31, 2000"

The expires date in Cookies has a specific date format, which browsers tend to
be quite picky about. The original date format was defined by Netscape to be
like:

  Wdy, DD-Mon-YY HH:MM:SS GMT

This is of course a stupid format as (a) it has a superfluous weekday, (b) the
weekday and month are names in a language, (c) it has a two-digit-year, (d) it
has a timezone in it ARGH, and (e) it's not a valid string from which to make
a JavaScript Date object nor a particularly easy string to generate *from* a
JavaScript Date object.

These days you can use a four-digit year and all browsers should accept it
(hopefully few of your readers will be using Netscape 3). But fiddling with
the rest of the format is not generally advisable (though I don't know of a
browser than complains if you get the weekday wrong).
and@doxdesk.com