h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Interesting you haven't mentioned the spry used by UK police forces (amongst others).

This also isn't actually CS gas, it's the compound in a liquid solvent, which is sprayed into the face of an attacker.

The theory is that a police officer would use the spray on a violent offender or attacker if they were in danger. I won't waste your time with my views on what actually happens.

The treatment for exposure to the spray is similar to the gas, but you will also also need to wash the solvent off the face - eye wash soloution would be suitable for this.

Most of the time, what happens is that people completely lose interest in attacking said police officer or members of the public until they recover, by which time they're normally in no position to do so. Unfortunately, not everyone's affected by it, and there is always a problem with the wind causing other people to be affected.

Some police services in the UK now carry PAVA. It's a synthetic pepper chemical, and it's... well... err... much more effective than CS.

Ouch.