HOW TO REMOVE CORRODED AAA BATTERY FROM MINI MAGLITE?

You got this backward. Remember your high school Chem Class? Car batteries are Acidic, and you use baking soda and water to clean up the terminals. Dry cell batteries are Basic, and therefore any corrosion caused by battery leakage is also basic. I keep a small plastic bottle of white vinegar in my workshop, just to clean up all these battery powered gadgets we have. Just wipe a few drops of acetic vinegar on the corroded terminals, and the white junk will disappear like magic. Usually the terminals will look like new, unless the cheapskate manufacturer used plated steel for the contacts. In this case, they might be rusted, and will need abrasion to polish up the terminals. An eraser on the end of a number 2 pencil works well to do the polishing. I protect the polished surface with some dielectric grease from the auto parts store, to help keep the terminal from rusting again. That terminal should be re-polished and coated each time you put in new batteries. Also, when the device quits, get rid of the batteries quickly. Dead ones leak. If you do not use it often, remove the batteries. For example, if I have a flashlight in the trunk, I will remove the batteries and place them AND the flashlight in a ziplock bag, to keep them together. You got this backward. Remember your high school Chem Class? Car batteries are Acidic, and you use baking soda and water to clean up the terminals. Dry cell batteries are Basic, and therefore any corrosion caused by battery leakage is also basic. I keep a small plastic bottle of white vinegar in my workshop, just to clean up all these battery powered gadgets we have. Just wipe a few drops of acetic vinegar on the corroded terminals, and the white junk will disappear like magic. Usually the terminals will look like new, unless the cheapskate manufacturer used plated steel for the contacts. In this case, they might be rusted, and will need abrasion to polish up the terminals. An eraser on the end of a number 2 pencil works well to do the polishing. I protect the polished surface with some dielectric grease from the auto parts store, to help keep the terminal from rusting again. That terminal should be re-polished and coated each time you put in new batteries. Also, when the device quits, get rid of the batteries quickly. Dead ones leak. If you do not use it often, remove the batteries. For example, if I have a flashlight in the trunk, I will remove the batteries and place them AND the flashlight in a ziplock bag, to keep them together.