how can i cookies clear when i close the chrome browser

Question

i want to cookie clear when i close the chrome browser.

explorer browser is no problem, but chrome browser is problem.

i close chrome browser, i open chrome browser and go site. still alive..

i need to your advice, please tell me.

thank you.

'### cookie create logic (log in process)
<NonAction()>
Sub setCookies()
   Dim aCookie As New HttpCookie("mysitename")
   aCookie.Domain = "mysitename.com"
   aCookie("userid") = "aaa"
   aCookie.Path = "/"
   aCookie.Expires = DateTime.Now.AddMinutes(600)
   Response.Cookies.Add(aCookie)
End Sub


'### cookie clear logic (log out process)
<NonAction()>
Sub clearCookies()
   Response.Cookies("mysitename").Domain = "mysitename.com"
   Response.Cookies("mysitename").Expires = DateTime.Now.AddDays(-1)
End Sub