Pure carbon monoxide is easily made with some simple chemistry and ingredients. Simply mix 2 part formic acid with one part sulfuric acid.
4.4.14 Production of Carbon Monoxide

Obtaining the ingredients is not hard or very expensive. Formic acid can be gotten here: Formic Acid, 96%, Reagent, ACS, Chemistry Supplies and Laboratory Chemicals Sulfuric acid is avaliable through some auto parts stores. It's used as electrolyte in auto batteries. I have seen it at Wal-Mart in the automotive section near the motorcycle batteries. Ace Hardware carries a drain cleaner, brands vary, look for a white bottle that is wrapped in a plastic bag.

Safety: Everybody knows that it can kill you with ease. I think it's safer to make the stuff as you need it rather than having a bottle around that could possibly leak. I would recommend using about 20ml formic acid and 10ml of sulfuric acid outside in a sealed cardboard box.
The other way you can kill yourself is to expose it to high temps, sparks, or open flame. It is combustable. It will blow you an your plants up or atleast draw much unwanted attention to your grow op.

As for it working to make female plants. I don't know. I'm still trying to decide if the risks are worth it. It seems to me if you get some females going, cloning is just easier.