old gas/turpentine

hi folks
any suggestions on how to dilute some old gas in a gas tank i took out of a 70 duster i just bought. there must be 6-7 gallons of gas that has turned into turpentine.i would like to dispose of it but as bad as it smells and it still will ignite so the old idea of digging a hole and poring it out won't work.so i'm looking for something to add to the gas that may eliminate the smell and not to ignite.
terry