Oxidized Copper Swords

An addition to copper swords (and other axes) should be oxidization. If not waxed, the tools will become oxidized over time. An oxidized tool will have its damage reduced by .5 for each level of oxidization, as well as losing durability much faster. But, as a trade off, the weapon will inflict 2 seconds of poison per level of oxidization.

I'd imagine the other copper tools would also receive similar treatment, though they'd need their own mechanics, as they wouldn't usually be used as weapons.