Coastal Eddie
Ambivalent
Dave,
Like Coastal Eddie said if you go with an acid solution start at the bottom and work up. This is very important because the acid will streak if you start from the top. It will surely make a mess and you might have a chore getting those area's corrected. Also you might want to wet the area first with water, just in case your mixture is a little strong.:inspector: :bigups :howdy
I forgot to mention in the other one that when using HFA or HCA, do not let it linger on a window for lengthy periods of time; especially on a warm day. It will etch the hell out of glass!!
"Very good" point about wetting the surface first, especially aluminum. It's also surprisingly easy to "fix" or even out your mistakes by just redoing an area that you don't like with different dilution, or like Dave said, spray it on a wet surface, and get at your rinse a little bit faster, and maybe more thoroughly from the top down......