"Aluminum brightener" can be hydrofluoric acid. Big truck cleaning, for instance, on wheels and tanks. Not recommended without experimentation first. I've used it for non-A/S purposes, but would be VERY concerned over it getting into seals, under rivets, etc. Etches glass.
1990 35' Silver Streak Sterling
; 9k GVWR.
2004 DODGE Cummins 305/555; 6-manual; 9k GVWR.
Hensley Arrow. 10-cpm solo, 18-cpm towing
Sold: Silver Streak Model 3411