Prepping/polishing aluminum for 'brite dip' anodizing

[mark369]

Anyone here have any experience with polishing aluminum to be brite dipped? Recently, I polished some aluminum automotive trim (using Caswell products, of course) Parts had a very nice mirror-like finish on them when I took them to a commercial anodizer, even looked nice when they came out of the brite dip tank. (they let me hang around to check out the operation) But after coming out of the anodizing tank, the mirror finish was replaced by what I can only describe as the appearance of being lightly bead blasted at a distance of a foot or two (still somewhat shiny, but 'freckled'). Kind of like the road rash I desired to get rid of in the first place. Is what I described to be expected of brite dip? Is there a 'tried and true' prep procedure to obtain the best results? Thanks in advance.