I was just cruising the web for completely non Halloween related things and stumbled upon this stuff. I'd never heard of it before, the claim from the site is:
"Highly efficient fog fluid designed for special applications. If you have a situation where the fog has to disappear before it reaches the audience in front of a stage, or a fire alarm system, this is a great fluid to use. Also works great in foggers coupled to low smoke machines for producing an efficient low smoke (low smoke machines should always use faster dissipating smoke so it doesn't heat up and rise, creating the look of a traditional fog machine. Also works well for burst of steam effects, etc. Great for situations where you need to clear smoke quickly and efficiently. Used in a staged performance setting, this fluid will create a perfect fog that dissipates completely as it rolls off the stage, before it can reach the audience."
Has anyone ever tried this stuff? It's not cheap, around fifty bucks a gallon, I was just rather curious.