Modern Warfare 3 Zombies has many new weapon camo skins and challenges for players to complete. Some of these even ask players to score toxic damage kills in MW3 Zombies, but those goals aren’t explained well.
How to do toxic damage kills in MW3 Zombies
Toxic damage kills involve using specific methods of eliminating the undead in MW3 Zombies. Unfortunately, if you’re a little lost, that’s understandable since the game gives you no tutorial on how to apply toxic effects to your weapons. It turns out there are two core ways in which you can inflict toxic damage in Zombies at this time.
For the first method, use Experimental Gas, one of the grenade-like items you can obtain. The key here is to throw the Experimental Gas into a group of as many zombies as possible. This gas deals the minor toxic damage you need to undead hordes. Better yet, if you fire at these zombies while they’re in the gas, that will also count as toxic damage kills.
The second way you can get toxic damage kills in MW3 Zombies is to find the Brain Rot ammo mod. This modifies your weapons so they fire off toxic bullets, instead of the usual ones. Unlike the Experimental Gas, you can use the Brain Rot ammo as much as you want within a match so it is a bit more flexible for getting toxic eliminations.
Where to get Experimental Gas and Brain Rot
Of course, before you can even land those toxic damage kills against the zombies in MW3, you’ll need to find these two items. This is by far the harder part of the process, as neither make for a super straight forward challenge. The Experimental Gas is by far the more straightforward option, as it is a tactical item you can equip on your loadout.
The only problem with this is you need to reach level 18 to unlock the challenge to unlock it through the annoying Armory Unlock system. Then, at level 18, you must finish five daily challenges while the item is in your Armory queue to unlock it. But once you have it, you can equip it anytime you want.
The Brain Rot ammo route relies entirely on luck. Open up as many supply crates as possible in Zombies matches for a chance to find this ammo mod. Once you find it, you’re good to go and can automatically deal toxic damage. I recommend looking, specifically, in the medium threat areas for a higher chance of locating this mod.