I don't want mrxvt to consume the Alt + <number> keystrokes

[Disc Magnet <discmagnet@gmail.com>]

I run irssi on mrxvt. When I press Alt+1, Alt+2, etc. it changes mrxvt
tab and not the irssi win.

How can I configure mrxvt such that it does not consume the Alt
key-stroke. It also intereferes with emacs style Alt+<number>
keystroke for repeating command that readline can understand.

So, please help me to configure mrxvt such that it does not consume
the Alt keystroke?