From: Mubix’s Links

This is exactly like the last script with a few minor changes. 1st, the last script only has the ability to force people to unfollow you if you aren’t following them. 2nd, the api call and the request URL are different. GetFollowers instead of GetFriends, and friendships/remove instead of friendships/destroy. Don’t forget to fill in the same 4 fields that were missing/wrong in the last one.

#!/usr/bin/python

import twitter
import urllib2

headers = {
'User-Agent' : "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729)",
'Cookie' : "__utma=",
}

data = "authenticity_token=&twttr=true"

api = twitter.Api(username='joeuser', password='password1')
for b in range(1,100):
users = api.GetFollowers(page=b)
for i in users:
request = http://twitter.com/friendships/remove/ + str(i.id)
req = urllib2.Request(request,data,headers)
post = urllib2.urlopen(req)
print post