I love the What’s Inside that Wired does every so often. You remember spray cheese from way back, right? This month they list what’s inside the miraculous Fix-A-Flat:

A type of fluorocarbon that doesn’t deplete the ozone layer, TFE is found in everything from cryogenic-tissue kits to car air conditioners. Here it’s used as a tire inflator, a drying agent, and a propellant for the other ingredients. Unfortunately, it’s also a greenhouse gas that’s been implicated in abnormal tes-ticular growth in rats – you must have some serious cojones to keep using it.

Heavy aromatic solvent naphtha
It’s not called aromatic because it smells (though it does – like petroleum). Aromatic is a scientific term referring to any molecule with one or more hexagonal rings of six carbon atoms. They can be unusually stable and powerful solvents for other hydrocarbons. Since naphtha is a mixture of medium-weight aromatic rings in the C9-to-C16 range (extra carbon atoms can hang off the sides of the main structure), it easily dissolves smaller carbon compounds like simple plastics but won’t harm larger polymers like styrene-butadiene (synthetic tire rubber).