Most of us toss away our car and boat batteries when they no longer start our vehicle in the winter. Most of these batteries are now advertised as maintenance free lead acid, even though the electrolyte often still dries out. Youtube user Redicety12 shows us how you can bring them back to life by cracking the tops off the battery, dumping out all of the old electrolyte out, rinsing with a baking soda and water solution, then a second water only solution. Now that it is clean he fills it with alum water. After a trickle charge the battery is brought back to life. Probably is not as good as new but will probably give you some additional usable life.