[RICK LAKE]

Omathisen First off, It looks like someone has some black stuff between the rim and the center cap?? RTV?? Some RTV eat Aluminum and corriode it. To get the center caps off I would try a large press with wood blocks to remove them. Antiseize needs to be coated on both parts. If that doesn't work easy, then adding a little heat around the rim and again try tapping out the center. The last thing would be to airgun or drill and grind out the centers and buy new center caps. Cheaper to replace centers than rims. If hitting the center use ONLY a BRASS, LEAD or DEADBLOW PLASTIC HAMMER.
If these things fail, call a rim repair man that can come to your house or place of work. Rick L.