Disposal of stale gasoline?

I have 20 to 30 gallons of 6-year old gasoline in my built-in boat fuel tank. The only way the hazardous waste disposal centers will take it is if I siphon the gas into 5-gallon portable tanks; limit 15 gallons. Even if I wanted to, the addition of small amounts of the tainted gas to my car tanks is impractical as I have no way to store it or dispense it accurately. My small motor engines need to stay relatively easy to start and they only burn small amounts of fuel anyway. The gasoline is so old that I wouldn't want to sell it to anyone. I'm not even going to comment on the "burn or evaporate it" solutions. My garage told me that they couldn't take the stuff off my hands. Is there any solution other than buying lots of 5-gallon portable gas cans and getting rid of it gradually at HAZMAT centers?