If zombies use sight as a primary sensory agent when hunting for humans, any weapon that can take out their visual ability should prove highly effective.
Imagine playing the children’s swimming pool game Marco Polo in silence. What are the chances that the kid who’s “it” would ever be able to catch anyone else with his eyes shut and no verbal clues? Practically zilch.
Blinding a zombie may not eliminate the threat completely, and if you’re faced with a hoard of undead ghouls, then you’ll need one massive spray bottle to blind them all. But it’s widely believed that zombies lack any defensive instinct, so they’d happily walk through a wall of toxic liquid to get to their next meal, making traps easy to set. A simple bottle of bleach might even work.
The point here is that there are a whole host of alternative, nonlethal zombie weapons worth considering, because you never know where you’ll find yourself when the zombie pandemic hits.
Killing zombies should not be your primary objective–getting away alive and safe should be.