无法删除简单的PHP cookie

I'm trying to make a simple members area. It was all working fine until I wanted to make a button in my navbar different if the user was logged in. I found that from the navbar include I couldn't access the cookie because navbar.php was in a different directory. So I searched Google and I found that I had to set the cookie's path to "/". After doing this my navbar worked flawlessly. I later found that my logout page had stopped working. After a lot of frustration I am unable to figure it out so I was wondering if I could get some help.

Here is my set cookie code from the login

$_POST['userMemberNumber'] = stripslashes($_POST['userMemberNumber']); 
$hour = time() + 21600; 
setcookie("ID_wragc", $_POST['userMemberNumber'], $hour, "/", ".wallingfordrodandgunclub.org"); 
setcookie("Key_wragc", $postPassword2, $hour, "/", ".wallingfordrodandgunclub.org");     
header("Location: membersindex.php"); 

and here is the code from my logout page

$past = time() - 3600; 
setcookie("ID_wragc", "", $past, "", ""); 
setcookie("Key_wragc", "", $past, "", ""); 
header("Location: ../index.php"); 

The cookie gets created just fine, but I can't remove it on logout.

Your expiry time needs to be >= your set time (21600) and also need the same dir and folder.

$past = time() - 21600; 
setcookie("ID_wragc", "", $past, "/", ".wallingfordrodandgunclub.org"); 
setcookie("Key_wragc", "", $past, "/", ".wallingfordrodandgunclub.org"); 
header("Location: ../index.php");