Air fresheners are the worse things you can put inside a car. What you're pretty much doing is putting perfume on continously to all the interior surfaces of the car. Think of it as a person putting on perfume/cologne daily without bathing.

Over time, the smell starts to turn into something else and it'll form fungus and people try to counter that by putting more air freshener to MASK the odor.

Pasama lang ng pasama.

The more you do this, the more ineffective air fresheners will become since the odor will now be more concentrated, the stronger the odor, the more it cancels out the "scent" you're adding.

Unfortunately, it's nearly impossible to get rid off all the smell in a short period of time. The odor has already stuck itself on all the upholstery, plastic and air conditioning paths in the cabin.

Once you start using air fresheners, your cabin will almost never smell fresh again until you clean the interior thoroughly again and again, airing the interior out until the smell gradually goes away.

Eventually, it'll smell like a cab.