Just add fuel. Save the liner for when you have no option. Option B: Empty the tank to completely dry. Spray the inside with some fogging oil or coat the inside with maybe 90W gear oil. That will keep it moisture free. Electrolyte is required for the rust to happen.I emptied my tank out and was surprised to see half a dozen, randomly located, light rust spots maybe 1/8” - 3/16” diameter. I’m thinking I should give then a soak in Evaporust before refilling it. If I do this, since the inside of the tank is otherwise in perfect shape, do I need to seal the inside of the tank with a liner or just add fuel?