Kill bad cookies in WebKit. Uses poor and incomplete heuristics to achieve its goal. Includes a LaunchAgent to run the script every night (path in that must be adapted for your account).

cookiekiller.py

#!/usr/bin/env python

"""
	COOKIE KILLER
	2010 by Sven-S. Porst <ssp-web@earthlingsoft.net>
	Script with simple heuristics to kill the most obviously crap cookies in WebKit.

	Available at http://gist.github.com/324414
	
	Better quit cookie users before running the script.
	Perhaps run it at login and nightly with a LaunchAgent?
"""

from Foundation import *


evilNames = ["__u", "CFID", "CFTOKEN", "CoreID", ".ASPXANONYMOUS", "ACOOKIE", "AdUserID", "AVPUID", "AWSUSER_ID", "awpopup", "Apache", "bitt", "BX", "CP", "Conversion", "DM", "FC", "GUID", "HstC", "HumanClickID", "ID", "IXA", "JEB2", "LE", "NGUserID", "OAID", "OASIS", "OAX", "POPUPCHECK", "RM", "SID", "TC", "TID", "TRUID", "UID", "UUID", "VISITOR", "VISID", "VisID", "VisitorID", "WEBTRENDS_ID", "WSS_GW", "WT_FPC", "_SUPERFLY", "_OA", "__a", "_bit", "__c", "_dw", "__g", "__k", "__q",  "__r", "_c", "_m", "ad", "anon", "bblast", "c1", "eid", "exp_", "emos_", "mds", "meta", "etcnt_", "fpc", "globid", "gmv", "goo", "i00", "iCmpro", "jehiah", "mojo", "OA", "omniID", "omniUserID", "otp", "pb", "phpAds", "pid", "piwik", "re_ret", "ref", "s1", "sUnique", "s_", "ss_lastvisit", "stat_", "suid", "TLTUID", "tu", "um", "v1st", "vid", "VWCUK", "WEBTRENDS",  "_w", "wlid", "woo", "wpgb_", "wt_", "XCLGF", "zF" ]

evilDomains = ["googleadservices.com", ".adlink.net", "advertising.com", ".ad",  ".doubleclick", "ad", ".statcounter", "track", ".hoc-technology", ".Adjug", ".pubmatic", ".webmaster" ] 

path = NSString.stringWithString_("~/Library/Cookies/Cookies.plist").stringByExpandingTildeInPath()
array = NSArray.arrayWithContentsOfFile_(path)



resultCookies = NSMutableArray.array()
count = 0

for cookie in array:
	kill = False
	name = cookie["Name"]
	domain = cookie["Domain"]
	
	for evilName in evilNames:
		if name.startswith(evilName):
			kill = True
			count = count + 1
			break
	
	for evilDomain in evilDomains:
		if domain.startswith(evilDomain):
			kill = True
			count = count + 1
			break
			
	if kill is False:
		resultCookies.addObject_(cookie)


resultCookies.writeToFile_atomically_(path, True)

print "Killed " + str(count) + " of " + str(len(array)) + " cookies."

net.earthlingsoft.cookiekiller.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>Label</key>
	<string>net.earthlingsoft.cookiekiller</string>
	<key>ProgramArguments</key>
	<array>
		<string>/Users/ssp/bin/cookiekiller.py</string>
	</array>
	<key>RunAtLoad</key>
	<true/>
	<key>StartCalendarInterval</key>
	<dict>
		<key>Hour</key>
		<integer>5</integer>
		<key>Minute</key>
		<integer>0</integer>
	</dict>
</dict>
</plist>