I do not discuss Mr Spangler (or anybody else for that matter) techniques, just pointed out that even micro scratches, the ones you do not see, favour micro arching on the wheels and the accumulation of non conductive oxides on the rail surface. That is why i am exceptionally careful on what i use on the rail surface. I use the german TILLIG which is also weathered, i think by chemical blackening, also to avoid isuues like that.