Yakup KALEBAŞI

public void DeleteCookie(string name)
{
    DateTime now = DateTime.UtcNow;
    string cookieKey = name;
    var cookie = new HttpCookie(cookieKey, null)
    {
        Expires = now.AddDays(-1)
    };
    HttpContext.Response.Cookies.Set(cookie);
}

Kaynak: http://www.aspmvcnet.com/tr/m/asp-net-mvc/cookie-silmek.html