text: how do you make gas out of common household items?   um, it depends on what you mean by gas. you can make methane by opening a can of beans and eating it. you can make ethanol which some people might call gas for cars (i call it booze) by fermenting pretty much any organic matter you have around the house from a sack of potatoes to your dirty cotton gym socks. you can set a glass of water on the counter and it will evaporate creating the gaseous form of water.