Getting rid of car smell. Smells like something crawled in there and died. ?

If you've cleaned all the upholstery, including between the spaces in the seat cushions and UNDER the floor mats, and it's still there, it's probably been absorbed into the carpeting. Try cleaning the carpeting with an odor-neutralizing carpet cleaner. If that doesn't work, I would take it to a place that steam-cleans interiors.

Maybe something did die under the hood or in the fresh air intake for the heater/AC. Check there. Febreeze is pretty good at killing the smells short term. Drive with the windows open or have the car detailed and shampooed inside.

Get the inside of the car shampooed you might have to start off with that and I heard that if you get a bag of apples and cut them open sit them in a bucket inside your car it will absorb the smell and also leave the car smelling like apples. Nothing wrong with that :-). Try it

set a bowl or open container in the closed in car some White Distilled Vinegar.

or

set a bowl or open containter of Acitvated Charcoal to absorb the smell.

you've disillusioned someone and they hidden a prawn (shrimp) head someplace on your seat, likely between the seat foam and the cover. An upholsterer could properly be able to help as they can get rid of the seat masking and discover the source.

I'd don't use chemicals in my home. There are plenty of 100% natural products available for you to use.

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