I have seen people recommending physical flushing to get rid of
the bottom sludge, which is sulphate primarily I guess, and then
replacing the sulfuric acid with another electrolyte (EDTA sodium?).
It seems to work on some plates and not others, perhaps having
to do with the presence or absence of calcium, antimony, or
whatever.
Electrical de-sulfation with a "zapper" is only going to remove the
plate-plate whiskers. It won't do anything for a sludge-bed
that shorts plates, or for loss of plate surface area from deposit
/ film.
At any rate I think you should begin with a physically cleaned
battery and then go knock off any filaments that remain.