Or, if your keyboard layout uses a different key (e.g., ¬ or ² ):
Steam\steamapps\common\Call of Duty Modern Warfare 3\players config.cfg : Open the file with a text editor like Notepad. Enable Commands : Search for seta monkeytoy "1" and change it to seta monkeytoy "0" : Since the tilde key ( how to enable console in call of duty modern warfare 3
bind ~ "toggleconsole"