I have been using the aluminum foil chrome cleaning procedure for many years and am usually totally impressed with the result...
Same fork cleaned up...
The only thing that I do to help preserve the shine is keep the chrome dry and waxed (I use Mother's Cleaning Wax cause that's all I have). So far, so good and the cleaned chrome on my Legnano has been like this for ten years or more...
However, if you want to be extra sure about oxidation prevention, coat the chrome with some clear lacquer as I did on my late fifties Rabeneick...