Lead acid batteries deteriorate over time due to the build-up of sulphur on the lead plates. When this happens, electrical current is impeded and the battery may appear to be dead. However, rather than spending more money than is necessary on a new battery, you can add some household chemicals to the battery to dissolve the sulphur, adding life to an otherwise dead battery. The chemical used is called magnesium sulphate, better known as Epsom salt, and is readily available in any pharmacy.
Put on your safety goggles and sturdy latex gloves and pry the battery open with a flathead screwdriver. There is a plastic cover that seals a bank of cylinders that lifts off the top of the battery.
Mix a pint of distilled water and 227gr of Epsom salt and heat until the salt is dissolved.
Tilt the battery into a sturdy plastic bucket until the cylinders drain. Use a funnel to fill the cylinders with the Epsom salt solution. Do not fill past the indentation line on each cylinder.
Reseal the battery by pounding the cover on with a mallet. Shake the battery to work the solution through each battery cell, being careful not to spill.
Charge the battery on a trickle charger overnight. Be sure that the charger will not overcharge the battery.
Dispose of the old acid according to your local regulations.