In response to the dent, I had a sharp crease in the left front of my tank. I took it off, removed the fuel tap and inserted a long rod through the open slot (where the tap was) and hammered the dent out. After the metal had been hammered out to almost the right shape, I then used the old fashioned method of leading and filing and then sanding for finish. You cannot tell it was dented by sight or by feel. Of course I lost the original paint and decals in the process, but now I have red tank with black frame and fenders. You could also finish with bondo if you don't like lead. One thing about that freezing process, ice is not educated to exert pressue exactly where you want it, it expands equally everywhere and you might not like the results.