Issue With Cookies Not Getting Deleted Even After Setting A Previous Date In Expires Property

I am using the following to delete the contents of a cookie

Response.Cookies("maincookie").expires = DateAdd("d",-2,now)
Response.redirect "login.asp"

If i try to alert the value of the cookie in the same page, it shows
the old value. As well as when it is alerted from the login.asp it
shows the old value.

The problem is when i try to update the value of the cookie in the
login page, it does not update the new value.

Only if i close the browser and reopen, the new value gets updated and
even if the old value is originally present in the cookie.

I am specifying the domain and path when creating the cookie. the
expires property is set to date + 1 when creating.

What should be done to delete the contents of the cookie? Should i
specify the domain as well as path when changing the expires property?