Here's what I do sometimes. I don't usually smoke in the car but sometimes i like to smoke one after I go pick up some food. turn on the ac/heater in the car, make sure it's blowing good and strong and only on the vents that's on your dash and feet. It'll suck everything in. so after you are done smoking just let it sit there for a minute and crack the window so left over smoke can exit. spray whatever you want and have airfreshner shit in your car and your good. only problem is the 50. get pulled over and your ass is gettin a DUI!!! i'm sure there's gonna be a little bit of smell left no matter what tho, but that ac/heater shit works. when u crack the window and smoke the smell can travel pretty far. that's why crack it open when you are done taking hits or whatever.