Use "expires" or you can send the cookie again with a null value "";

Ex:

use CGI qw/:standard/;
use CGI::Cookie;

my %CookieVars = (
   ISAUTH    => $ActualCookieVars{ISAUTH},
   USERNAME  => $ActualCookieVars{USERNAME},
   AUTHLEVEL => $ActualCookieVars{AUTHLEVEL},
   MYNUMBER  => "$mynumber"
);

# set cookie to the user
my $cookie1 = new CGI::Cookie(
   -name=>'Test',
   -value =>\%CookieVars,  # var to be sent
   -expires=>'+1h',        # time to expire
   -domain=>"teste.com",   # domain
   -path=>'/', #option path
   -secure=>0 # no ssl
);
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