PCR battery charging

Years ago Periodic Current Reversal battery chargers were a good idea, letting you re-charge a standard zinc-carbon battery (or, I believe, an alkaline battery) without it blowing up, by alternating forward charge half cycles with lower voltage reverse half cycles.

Well, anyway, with modern battery chemistry, are these still a good idea? Even only one recharge cycle would be useful, but I don't want to make an explosion!

No not really. There have been some commercial attempts at marketing rechargeable alkaline but now that Lithium has succeeded so well there's really no point in developing it anymore. You could get away with a few charges on a generic primary cells but you'll lose capacity with each charge and I wouldn't trust it if you intend to discharge the packs at a high rate.