Kevin said blister agents (a category of chemical weapon) would work on zombies. That would be a major force multiplier for any defensive or offensive force. And the best part is these agents are fairly easy to manufacture. Speaking as an engineer, many commercial chemical plants could be re-tooled fairly easily to make a number of chemical weapons in bulk, and as I detailed in the linked discussion above, can even be made in your kitchen. Combined with conventional indirect fire support from artillery or mortar batteries to mutilate the corpses and deal with large numbers of enemies, you could definitely deal with massive hordes.
Using chemical weapons would also make retaking cities MUCH easier. Gas the city, or a portion of it, and then move in to destroy the corpses before they can revive. And if for some reason you cannot take a city using chemical weapons, carpet bomb it into dust or nuke it, then pick off any zombies that survive or revive as they emerge from the rubble with conventional forces supported by chemical weapons.
Make decapitation and cremation mandatory on death. All soldiers or defensive forces should carry a grenade or other explosive device that can be quickly activated, instructed to only use it in case they are overwhelmed. This way the only human bodies that would revive as zombie reinforcements are those who die alone and don’t manage to self destruct.
