So that's the case - I have a camp stove and a bottle of liquid fuel for it (gas? benzine? petrol? ah, whatever). Hike is over and I have to get on a plane - thus I have to get rid of this fuel. How do I do it? Or maybe there's no way to do it right and I've got myself a problem?
While writing the question, I've figured out an answer. I just burn the fuel in the stove.
Maybe this little knowledge would be helpful.
I was recently in Mexico and bought some unleaded gas at a gas station as stove fuel. I gave the unused fuel away to a taxi driver to put in his car.
I suspect the same thing would work fine with the fuels sold as "white gas" or "camp fuel." I've heard conflicting information about exactly how this stuff is formulated, and for all I know it depends on the manufacturer. But what everyone seems to agree on is that it's extremely similar to unleaded gas. Given the similarity, if a car owner has 20 or 30 liters of gasoline in their tank, I don't think it will hurt anything to add a half liter of white gas.
Here are a few methods
If you have a lawnmower or weed eater you can dilute your gas by about 5% to 10% with it and burn it off that way, even if the fuel is 'bad'.
Additionally, many fire departments will accept all manner of fuel, good or bad, and use it for backburning areas preparing for the summer fire season.
Some auto parts stores will accept fuel for disposal. Almost all will accept old engine oil. I suggest you call an auto parts store in your area as the acceptance of fuel is regional depending on what government services there are to pick up the fuel. Oil is recycled and all auto stores accept to the best of my knowledge.
What's the problem? The guy at the airport will take it from you. Proper legal disposal is now his business.
There might be a kiosk for dropping items you forgot to leave at home, before dealing with people.