Hello friend
Deleting a cookie—physically removing it from the user's hard disk—is a variation on modifying it. You cannot directly remove a cookie because the cookie is on the user's computer. However, you can have the browser delete the cookie for you. The technique is to create a new cookie with the same name as the cookie to be deleted, but to set the cookie's expiration to a date earlier than today. When the browser checks the cookie's expiration, the browser will discard the now-outdated cookie. The following code example shows one way to delete all the cookies available to the application:
HttpCookie aCookie = default(HttpCookie);
int i = 0;
string cookieName = null;
int limit = Request.Cookies.Count - 1;
for (i = 0; i <= limit; i++) {
cookieName = Request.Cookies(i).Name;
aCookie = new HttpCookie(cookieName);
aCookie.Expires = DateTime.Now.AddDays(-1);
Response.Cookies.Add(aCookie);
}