This is how you put letters or words that are not aloud in your clan.
1) Go on mw2 press clan tag
2) Type in a word that is not aloud but do not click enter yet!
3) So once you have that word turn off your modem or rouder. I think if you have a lagswitch you can turn that on and wait couple of seconds.
4) Now once you turned off your modem or rouder click enter.
5) It should sign you out.
6) Sign back it and there you go you will have it
I hoped this helps some of you.This works on all cods.
It is really simple. Go on your clan tag click it type in any word and then turn off your router or modem then press enter. Now it should freeze in 2 minutes it will sign you out then you turn on your modem or router click xbox live then there you go you have that clan.
You can do it with a lagswitch but you need Net tools