Thanks for the tips and insights. The rubber eraser being the most benign, I think I will give that a go first. Second up will be the flitz or simichrome, since it seems there is less chance I will end up with unsighlty scratches with those than steel wool. The original finish is not far from mirror anyway, so I am not worried about overshining it. I will post to let you all know how it goes.
Not surprisingly, the discoloration only occurred after a particularly hot day (mid-90's). On several previous occasions in cooler weather I had neglected to immediately wipedown without any problem. I also happened to wear a glove on one hand that day because of the hot barrels. It could have been the glove, although I doubt it. In any event, from now on I will be more careful.
