In the old days on my
dad's commercial fishing boat we had 8Ds with tar tops. When they went bad
you'd take the battery
up on the pier, take the caps off and let all the hydrogen vent, empty the
battery of electrolyte (stored in a pail), torch the top till it got soft
enough to pull the case away, then take a hose and blast away all the gunk
between the plates. Put it all back together, put the electrolyte back in,
reseal the tar and use it for another couple of years. We were dumb to do
this, but at least we wore goggles and full raingear to protect ourselves. I
swear 8Ds were tougher and heavier back then. It took two strong people to lift
them in the old days and now I can lift an 8D by myself with some effort.