University of Texas alum Laura Belmar, who now lives in San Francisco, has created a bottle for baby that uses a mason jar. Right now the bottles are available online at kickstarter.com/projects/masonbottle/the-mason-bottle. For $10, you get two Mason Bottle nipples to use the jars you already have. For $12, you get a mason jar, silicone nipple, metal lid, collar and plastic cap. Why use a mason jar? They are easy to clean because of the wide mouth, easy to heat because they are glass, and inexpensive and easy to find.