Getting off F350 dually (decor) center caps is tough. There are 6 very stout/grippy hex-sided steel lug clips attached to the backside of plastic chrome center caps. The OEM lug wrench has a notched end but the deep dish of the dually wheel makes it useless (works fine on SRW trucks).
On the backside of the dually center cap are six stout steel hex clips in six of the eight lug positions. I'd post a photo of the centercap back-side but could not determine how to upload it to the forum. We're thinking of removing two of the 6 clips to make center cap removal easier while still having a god amount of retaining grip for the dually center cap.
For a removal tool, we heated the flat tip of a medium-sized crowbar and put it in a metal vice and used a 5 lb hammer to bent the top 1/2 inch over at 90 degrees - to use as a center cap removal tool. Using the vinyl covered notched flat tip (also tried the bare tip) of the OEM Ford lug wrench didn't grip the dually center cap for us. SRW center caps are no issue. The deep dish of the dually wheels makes the OEM lug wrench useless but again works fine on SRW F250/F350 SRW trucks.
BTW, the center caps "Made in China" as are the aluminum OEM Ford dually wheels. I could not locate a country of origin stamp on the Ford OEM steel dually wheels). Our high-performance 2016 Shelby GT350 wheels are also made in China...