1968 I left a bag made out of burlap with about 30-45 crappies in it in my trunk for about 5 days during the summer.
Parked the car after a day of fishing and having a beer or two and forgot the fish, rode the bike all week to work and the following sat I was going to use the car.
Just about threw up when I got in it.
Cure?
Brought it to a auto detailer who pulled everything out of the trunk, including matts and insulation and then cleaned what was left, not sure what they used but it still had a faint fish odor for a month or so after that.
I’d pull out whatever the fish guts were sitting on, clean under it and replace mats, insulation, etc…and hope..:)
Al