You can't. Forget all those remedies others have come up with to satisfy your delimma. They sound good but just don't work. Like where you gonna find a rag or a spatula when you need one?
Just get yourself a big flat tip screwdriver and a heavy duty ball peen hammer. Insert the blade of the screwdriver under the lip of the hubcap and then, whilst holding the handle steady (so you don't bust your knuckles) smack the end of the screwdriver with the heavy ball peen hammer. Make a real good solid hit on it so the screwdriver makes just one pass under the hubcap's lip and then travels all the way to the other side of the wheel.
If you do it right you won't have a bunch of little scratches where you have worked a little screwdriver back and forth trying to gain purchase. The large ball peen assures success with just one lick. Also, it makes the hubcap pop right off and skid, with face down of course, across the cement garage floor. The scratches left on the chrome or stainless steel will give the hubcap character and enable you to not worry ever again about getting it off without damage. Works for me. You know.