I've tried the usual auto store products to no avail. Recently, someone recommended a Lexol product for black plastic. While it looked good for a couple of weeks, the white residue seems to have returned. I suspect my wife got wax on it when she waxed the car due to the ghost images I see in the whitening and the fact that its only on one side of a black spoiler.
Are there any good products or procedures to remedy this?
Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
You might try a tooth brush. I use as soft a brush as I can to get wax out of the nokes and crannies of park lights, trim, etc. As for the spoiler, I would use some windex on the tooth brush and lightly brush it and see how it comes off.