For 30 years this steel 150 gallon portable refueler tank has served me well for off-road vehicle refueling. It get filled 2-4 times a year with non-oxygenated premium gasoline that I use for boats, lawnmowers, snowmobiles, quads etc. Decades ago I welded up a frame to secure it on the axle of an old snowmobile trailer. It's never on the highway, but is portable for the purpose of towing it across the yard down to the lake for refueling my boats, one of which has a 60 gallon tank. The tank is intact, but the bottom is rusting to the point where it's pretty much done for. I don't want to risk a gasoline spill so I've purchased a replacement tank.
My question: Anyone have experience with decommissioning an old gasoline storage tank? I'll pump the gasoline out of it of course, but then what to do with the tank? The landfill will take it, but I'll want to cut it up for that and I'm not sure how to decommission the tank, what to do with the contents that's environmentally safe, and renders the tank safe for cutting it up (Sawzall vs plasma).