Anyone try to rejuvenate a lead acid battery?

I have a couple of lawn tractor batteries that appear to be sulfated (normal voltage but will not take a very large charge). There appear to be a couple of methods to rejuvenate them but I'm skeptical they work.

One is the battery "desulfator", an electrical gadget you connect to the terminals and it sends voltage pulses into the battery that supposedly remove the lead sulfate coating that has built up on the plates.

Another is a chemical procedure in which the liquid from the battery is drained and the battery is flushed with a baking soda solution. A concentrated solution of Epsom salts (magnesium sulfate) is then added and the battery is recharged/discharged a few times to supposedly restore it.