Then, how do you get carbon monoxide out of your house? You can do this by opening all windows and doors in order to allow fresh air entering your house and get the carbon monoxide gas out of your house.
This is very important to do since fresh air will decrease the level or concentration of carbon monoxide gas inside your house. Do this until the detector stop beeping.
Actually, this procedure is already described in this website, i.e. How to act against carbon monoxide detector beeping.