How can I get rid of gasoline odor inside my car?

I put a gasoline container with just a bit of fuel in it in the back seat of my car for a few days last summer. I noticed the gasoline odor when I next drove the car and took the container out soon after. The odor remained. I burned a candle in the closed car for several hours, and that seemed to reduce the odor but didn’t eliminate it. I still notice the odor every time I get in the car, even six months later. I don’t think any gasoline spilled from the container, but the odor remains.

Can anyone advise me how to get rid of the smell?

Even if you did spill some, gas evaporates pretty fast. Just having a gas can in their for a days, I’d have thought the smell would dissipate within a few hours.
If covering it up doesn’t work, maybe try something absorbent, like activated charcoal. If you have a cabin filter, I’d replace the filter with a HEPA filter, if possible, and run heat/ac on recirculate for a while and leave the windows cracked when you’re not driving it.

But 6 months later?
Can you smell it before you get into the car? My concern, at this point, is that it’s not coming from inside the car, but rather you have a fuel leak somewhere. Next time you drive somewhere, after you get done, you could try looking/smelling around under the car as well as in the engine bay and see if you can see or smell anything.

I keep the car in the garage with windows closed. I don’t smell anything in the garage or when I get near the car, but I immediately notice it when i open the door and get in.

Then it’s probably not a leak, but like I said, gas evaporates quickly.
I’d still go with some activate charcoal and/or leaving the windows open overnight.
If you have a (household) air purifier with a HEPA and/or charcoal filter, you could set that in the car and run it for a few nights.

Also, now that I think about it. Look in every nook and crannie of your car with a flashlight. Under the seats, in the trunk, glove box, under the dash, pull the blower motor to check in there if you’re handy and make sure there isn’t a dead mouse or other small animal putrefying.

A while back my garage smelled like butane. I spent half a summer trying to figure it out. I took everything in my garage (blow torches, propane tanks etc) out and it still smelled. There’s no natural gas lines running near or through it, but I looked into that idea as well. After a few months of trying to figure it out, it ended up being a dead, decaying squirrel. Oddly enough, when I was looking around on the internet trying to see what could make my garage smell like butane, ‘dead squirrel’ came up a lot but I kept dismissing it.