Sometimes when your car had a leak - either in the boot or to the front mats - it does have this kinda smell. I should know when my boot had a bad leak from the rear-lights.
I had this product of the supermkt shelves - "Febreze" and it cleans odour away from the fabric. It worked. On top of that, I stuck a couple of charcoal to absorb whatever smells there were - .
I had the a/c ducts cleaned too ... now the car smells good.
Its good to get to the root of the source and overpower it.
126 tailed by a 203, 129 leading the pack.