Do a full interior shampoo/extractor be careful not to get interior to wet mayincrease smell n cause mold if it doesn't dry properly! When complete with that u can take apart dash and clean allthe build up of ash and tar in the vents andin cracksalso back of plasic pieces. When done with that put a de-ionizer in the carand run it for a few hrs after replacing cabin filter. After that ifu like u can place some liquid smell good in the I take of ac and run ac for awhile