You donkey, there's nothing to recharge in a Zerostat.
You have a later model than mine, place your 'recharge' item in the muzzle, then in a dark room work the trigger, you should see the 'item' glow faintly, that tells you the Zerostat still emits ions.
In still older ones like mine, the 'item' is embedded in the wooden stand, you have to get the Zerostat positioned 'just so' to make it glow, and either I've lost the knack, or mine is dead.
Recharge......