That is the whole purpose of a Carbon filter, to eliminate smells, a normal filter, no matter what you do to it, will not counteract smells for any prolonger period. Spraying a normal filter with an odour spray will only last for a small period of time, a carbon filter will operate thoughout it life cycle. Don't be a cheapskate, do the job right. Look after your car, and it will look after you, has always been my motto. If you are not going to do a job properly, why do it at all.