On the 4th of July, a two-gallon can of gasoline overturned in the trunk of my car; about half of it spilled all over the trunk. The trunk has a piece of carpet in it, and a removable felted cardboard-like panel underneath the carpet that covers the spare tire well.
I took the carpet and the cardboard panel out, and shampooed them thoroughly. I took the spare tire out of the well and mopped up all the gasoline that was in the well. Actually, when you open up the trunk and stick your nose in there, it doesn’t smell like gas at all.
But the interior still smells of gas. It’s smelled that way for three weeks. Any suggestions? Absent that, any idea how long before the car doesn’t smell of gas anymore?
Gas is a volatile, so eventually it will all evaporate and leave. Leave the car open as much as you can, preferably where the breeze can blow through it. Between weather and critters and tree-crap, that’s not always possible. But I think extensive airing out is your only solution short of stripping the interior and cleaning every piece of it.
I just think I should point out that carrying gas in the trunk is very, very dangerous.
This little spill you had could have turned into an explosion when you opened the trunk and the trunk light came on.
While I do agree that carrying gas in a can in the trunk is dangerous, I am sure you are aware, most folks do not own a fuel truck, so their options are limited. Just stating the obvious does no one any good. I suggest that you let folks know how to mitigate some of the danger.
I suggest that they take precautions. One would be to put the can in a tall tub to catch any spills. Another would be to wedge the can against something in the tub & in the trunk so it can not slide around. Put this tub as close to the rear seat as you can, so that in case of a rear-end accident , the fuel can is not likely to be compromised. Of course no smoking in or around the car while the can is in the back.
As to the OPs original issue, Time is on your side. Let it air out as much as possible. You could wash down the bare metal of the trunk with soap and water. Rinse with water and let dry. After this much time I am not sure how much washing the trunk will help though.
Buy a high-quality marine fuel priming bulb and a suitable length of fuel hose - maybe 4 feet long on the input and 2-3 feet long on the output. When needed, use it to pump/siphon gas into a can for mowers, generators etc.
It’s a safe, cheap and convenient way to avoid transporting gas in small containers, running out, or having gas go bad. But don’t try it with a five-dollar hardware-store gizmo. Get one of those hard rubber bulb priming pumps for small boats, and real fuel tubing.