I have heard all my life that gas and diesel gets into the pores of the metal. Recently I read an article that said that is not true. Now when you talk about residual diesel left in tank, is that a few drops of liquid or what might be in the pores? I have two 003’s . Tank one was bone dry but rusty and a sorta dry white substance . I could not wipe that white stuff off the removable fill tube, I assume it is alge. A wire brush took some of it off, but no way to get to the rest of the tank that has it. Tank two has what looks like 4 gallons of diesel, water etc in it along with the white stuff and it is like a paste, wipes off but leaves a thin coat. From what I have been able to get from the net, there are a couple of fuel treatments that will kill alge, if it is alge, when added to fuel. Tank one is getting electrolysis and red kite. Tank two tbd later. Any thoughts on the subjects?