I believe you can now get "fluffy dice" which double as air fresheners. Not too hard to fit, but does entail removal of rear view mirror and electrics.
Just imagine how classy it will look! and sweet smelling too..
This one's so easy I'm surprised you need to ask.
You simply remove the doors and confine your driving to cherry orchards at blossom time.
Try having my problem. The car facing the wrong way.
I can't work out if this is a serious thread or notbut the best thing to get rid of smells are the little gas fumigator devices used for killing bacteria in aircon pipes.
They do an excellent job of neutralising smells in the car. Halfords sell them, and supermarkets sometimes have them too.