To find out what's left in the iptables do : sudo iptables -L
and if you want to flush all rules: sudo iptables -F

But, before do check carefully what you want to do and what firewall you want to
keep active. Keep only one firewall or you're set for troubleS.

Learn to program yourself the iptables at the following address:
http://ubuntuforums.org/showthread.php?t=159661