Problems with deleteing cookies

[ASCIIDuck]

I never thought the log *out* script would wind up giving me trouble! When I use Firefox, the following code segment doesn't delete the cookies, so the user isn't logged out, however, it works in IE. Any idea how to fix this?
<?php
setCookie("username","",time()-50000);
setCookie("keyid","",time()-50000);
header("location: http://ronksales.com");
?>

[hackerkts]

What about trying to use this
[code]<?php
setcookie ("username");
setcookie ("keyid");
?>[/code]

[ASCIIDuck]

That did the same thing as what I had.