without having read all the other good (and bad) suggestions I will tell you that I burnt up over 100 gallons of old fuel I had to take out of my boat one year. The main fuel tank had become badly contaminated with sea-water (bad vent) and I had to empty it. I used an electric fuel pump to move it into 5 gallon glass bottles (water bottles) I decanted it. By that I mean that I let it set for a day and let much of the crap in it (including a considerable amount of water) settle to the bottom. Then I poured off the top, through a clean rag to act as a filter, into another can and then into my old Chevy truck (350, single 4B Carb) where it worked just fine. I would be hesitant to put the stuff into a lawn mower. I don't know about you guys, but my lawn mower cost me an arm and a leg (way more than my first three or four cars cost combined), and I have enough trouble keeping it running right as is. That thing gets nothing but the cleanest of fuel and oil.
