There have been many types of supposed battery rejuvination methods projected over the years. None have become consistant standards it seems. some like javex may have been even dangerous. Thats because all they offer is usually very short term relief periods I suppose.

Keeping the electroylite level up and using the battery normally seems to give maximum usable lifespan. I have come to believe that a battery out of service for prolonged periods like the wintertimes should have the electroylite dumped out. Otherwise sulfation seems to develop quickly.

Then just before reusage is to resume put the electyolite back in. Use a full face mask when dumping and rubber gloves plus old clothes of course. Store the solution in a stoppered glass bottle. The battery will be at the same charge rate as it was when the electrolite was removed for all practical purposes next spring.

If it's good enough for the U.S. navy to get fifteen years out of their batteries subject to many storage periods it's good enough for me. Whatever you do just do not drain a current manufactured lead acid battery way down. It seems to really effect their lifespan drastically in far too many cases.