what is it called when blue stuff comes out of your batteries?
Rating Newest Oldest. Best Answer: The blue stuff around the battery is battery crud (scientific terminology) from the battery acid. You go in the house and take the baking soda box and a spoon out to it. Mix the soda with water in a pan, and using the spoon, spread it around the blue stuff, and generally, just all over the battery and nearby. You will see it react and bubble up. Use a lot of the soda and water, and when you think you have got it all, take the hose and rinse it off. It'll look a lot better afterwards.