Ok guys, thanks! I juts tried SOS pads, and the waxy buildup is gone, but the sidewalls were no longer pitch black. It seems like there are white "scratches" in the sidewall, but it may be the waxy residue that was rubbed around with the SOS pad, and did not come off all the way. Anyway, I applied some low sheen Formula 2000 protectant, and they are black again. Hopefully, the waxy buildup will not come back. I will drive the car tomorrow to see.
If the waxy buildup does reappear, I may try the WD-40 idea.
