Cheese, Spam, sardines nothing really good has ever come from a can. Hair is no exception. Hyped breathlessly on off-hour infomercials, spray-on hair is supposed to cover up bald spots. In practice, the can emits a fine powder that ends up looking a little better than if you had used a can of spray paint. If nothing else, it's evidence that there's definitely something to be said for growing old with dignity.