In looking it up I discovered that formaldehyde has several uses, the most well-known (and scary) being for embalming cadavers, but it is also frequently used in certain resins and plastics, notably in the automotive industry. It also has disinfectant properties that kill bacteria. That said, it is a known carcinogen and is highly toxic, so you'll have to excuse me if I don't declare myself a formaldehyde fan.
Forget the pine tree air-freshener, skull gearshift knob, and fuzzy dice... the next time I buy a new car, my first purchase to pimp my ride will be the biggest box of Car Formaldehyde Decomposition Scavenger I can find!