What I used to restore my mail from claws-mail imap caches after the servers disk died with to old backups.

gistfile1.py

#!/usr/bin/env python
from email.parser import Parser
import smtplib
import sys
import os
from hashlib import md5


def sendmail(mail_str):
    headers = Parser().parsestr(mail_str)
    print "Sending: '%s' from %s to %s" %(headers['subject'], headers['from'], headers['to'])
    smtp = smtplib.SMTP('localhost')
    #smtp.set_debuglevel(1)

    smtp.sendmail(headers['to'], ['[email protected]',], mail_str)

def is_sent(mail_str):
    db = open('/home/avraham/mailer_sent.md5s').readlines()
    hash = md5(mail_str).hexdigest()
    if hash + '\n' in db:
        return True


def mark_as_sent(mail_str):
    hash = md5(mail_str).hexdigest()
    db = open('/home/avraham/mailer_sent.md5s', 'a')
    db.write(hash + "\n")
    db.close()

new_mail = 0
old_mail = 0

if len(sys.argv) > 1:
    for mail in sys.argv[1:]:
        if os.path.basename(mail).isdigit():
            mail_str = open(mail).read()
            if is_sent(mail_str):
                old_mail += 1

            else:
                new_mail += 1
                sendmail(mail_str)
                mark_as_sent(mail_str)

print "Old: %s\nNew: %s" %(old_mail, new_mail)