How to remove the cookie set by
javascript:void(document.cookie=”PREF=ID=20b6e4c2f44943bb:U=4bf292d46faad806:TM=1249677602:LM=1257919388:S=odm0Ys-53ZueXfZG;p
Your cookie domain is .google.com, if you're not actually running the code from that domain you will not be able to modify the cookie.