OK, raise your hands - who is frustrated at the wax residue on your car's black vinyl bits? Me, Me!! Me - hand WAY up! I have white schmutz on my bumper inserts, windshield washers, headlight washers and door moldings. I'm just not dedicated enough to mask before I wax or polish.
I've asked the experts. I've tried alcohol. I've tried Meguiar's #40 and Trim Detailer. I've tried 303 Aerospace Cleaner and Protectant. I've even tried peanut butter. If you've tried all this stuff, you know that NONE of them work. Most have oils that completely hide the white stuff - looks great - until you've washed a few times. Then it all re-appears. Even if sufficient scrubbing with any of these would actually remove the residue, you can't see what you're doing because the 1st application hides it entirely.
So I'll try anything (which explans the peanut butter episode - THAT is how desparate I am

)
I recently found a can (metal can) of 3M "Adhesive, Tar and Wax Remover" pn #03607 - at a Wal-Mart, no less. This is a clear liquid, and is some sort of solvent. "Will not harmmost cured automotive paints" "Hmmm. Must be strong stuff", me thinks. It smells very similar to "Goof-Off" if you're familiar with that. Guess what - it works! I used an old t-shirt and a toothbrush - and the residue is gone. It takes a little scrubbing with the brush - the stuff has to "soak" for a little while - and of course, while it is wet, you can't see whether you've succeeded. But the best thing is this stuff evaporates completely away within seconds, (it helps if you give a soft wipe with the t-shirt to remove any excess) so you can SEE where you need to keep working. When you're done, the vinyl will look a little dull - but it will be free of wax. So - after it is clean, you can put your favorite rubber/vinyl dressing on and know that you aren't just temporarily hiding the wax.
I feel much better now.
P.S. - I found kids' electric toothbrushes on sale at Walgreens - $1.99. I'm not kidding $1.99!!! I actually used it to work in the tight corners.