I was always told anything that contains or contained a fuel or combustible should be drained and filled with water or other noncombustible while cutting to avoid spark. For smaller capacity items sand works as well. I have used it on items like vehicle gas tanks. Since they are getting cut up a little extra dirt wont hurt anything anyways.

I would suggest a plasma or stick welder if you use sand to prevent premature wear on any blades.

I would personally see a tank like this having better repurposing / resale value than scrap personally. People have used them in the past to make rocket stoves or barrel stoves since most are heavier metal. I have also heard of them being modified into furnaces for melting scrap for casting.



The few that I have encountered are around 1/4 inch thick which would make it very ineffective and time consuming to try to use a cut off wheel on a angle grinder.