Originally Posted by
Cl904
Get a piece of aluminum foil wet and rub the rusted chrome. The oxidized chrome gives up its oxygen atom to the aluminum and created aluminum oxide which helps shine the chrome... so no rust and shiny chrome with no chemicals.
Is that what you think it is or is that what you know it is going on?
My hypothesis -
The iron beneath the plating rusts and opens pits (pitting). The rust protrudes from the pits. Scraping with foil mechanically abrades the rust and deposits aluminum onto the rust, thereby coating the rust. The pit is still there. The rust might still be there (under the aluminum). The eye is not sensitive enough to discern the reflectance difference between small dots of aluminum against a large field of chrome plating.