I'm not certain which wheels you are referring to but on my GT/CS wheels, to be sure to not damage the center caps, I removed the wheels.
* you will need a small flat blade screw driver and a pr
of small needle nose pliers
* from the inside of the wheel you will see a split retaining wire around the inside of the cap
* pry one end of the retaining wire away with the small screwdriver so you can grab with the the needle nose
* after releasing the retaining wire from the full inner circle of the cap
* the cap will push out from the inside.