They should be packed with grease, also they are made of brass so really should not be seized. Judicious application of force in the correct direction should be all that's needed, but that may mean an extension bar, or - as I have found - the MWS tool (just £15) and a good plastic headed hammer. I really struggled with the OE factory tool and "lead" hammer, much cursing and swearing and bruised fingers, now it's no problem.
