Mustard Gas: This gas, which causes victims' lungs to fill with fluid and drown them from the inside, was commonly used during World War I. It has since been banned, but some still find ways to use it.

Nerve Gas: This horrible gas was used to interfere with the mechanism that transfers signals from the nervous system to the organs.

Pepper Spray: Although this is banned from warfare, police officers and civilians continue to carry pepper spray for their own protection.

Plastic Landmines: They're just as dangerous as metal ones, but they're infinitely harder to find after wars end.

Bio Weapons: Banning these weapons is just plain common sense when you can't ensure that they won't come back to hurt your own people.

Napalm: Because napalm cannot be used in wooded areas or near civilians, it's rarely used at all today.

Landmines Incapable Of Self-Destructing: In 1980, it was ruled that landmines that can't self-destruct after a certain period of time can no longer be used, since they pose an obvious threat to civilians.

Poisoned Bullets: Poisoned bullets have been banned since the 1675 Strasbourg Agreement.

Balloon Bombs: These were outlawed after the Japanese actually used them to start forest fires in Oregon, killing a Sunday school teacher and five children during World War II.

Salted Bombs: Unlike most nuclear weapons, salted bombs contain isotopes that make detonation sites uninhabitable for long periods of time.

Diseased Animals: Purposely releasing disease-ridden rodents and insects in war zones is no longer permitted.

Bat Bombs: Tested but never used by the U.S. government, strapping bombs on bats might have seemed like a good idea, but there was no way to ensure that the animals would fly to the correct locations.

Spike Pits: Containing spikes that were often smeared with fecal matter to induce toxic shock, these pits have been banned since the Vietnam War.