If vehicle has any issues including cleanliness and or odors it should be brought up before leaving lot.

That being said some smells only become apparent after being on road for a bit; especially with windows closed an AC or heat on. Things like vomit, urine, certain foods, etc.... You can bring these things up when returning vehicle, but don't count on getting any sort of compensation. You *might* depending upon manager or counter rep; but again each situation is likely to be different. Your other option is to contact EC customer service and see what they can or will do; again YMMV and nothing is certain.

If you are getting consistently same smell from different vehicles but same location; it might either be from certain frequent renter, hiker or other National employee who actually drives a vehicle. Garage attendants and or others who move vehicles within a garage/lot don't normally fasten seat belts.

Removing perfume residue can be difficult to impossible. Sometimes even laundering or dry cleaning fails to do so, at least initially. It may take more than one shot with subsequent airing out in between to deal with issue.