I never have used Gord's" polish, but it may be a good product. You can seal your aluminum grille after you pollish it, but if it is one of the grilles that has the finned aluminum bars, then the sealer may be more of a time consumer than a return for your money. I use a metal sealer from th eWizard's Line that is good and I am sure there are other brands out there, because I have used some before.
See this website for info
http://www.wizardsproducts.com/store...&cat=24&page=2