I have been struggling with the carpet smell, which is a combination of 27 years of old carpet smell mixed in with moisture, mice droppings, and a million small pieces of what looks like yellowish horse hair from the carpet underside.
Last night I pulled out most of the carpet and padding and ran the vacuum to cleanup the car... After work today I went back into the car for a quick drive and noticed that the smell was pretty much gone----lesson learned, I should have done this three years ago....!!!!!
Trunk photo: