you can use a hand impact for removal,but chances are you will mess some of them up. if you do not wish to risk removal of them,,i would try this. use your steel wool lightly to clean them, blow everything off with air and cover the screw heads with vaseline then paint your covers. when you wipe the vaseline off,if you missed a small spot on the cover around the screws spray a small bit of paint into the can cap and then use a q tip or small artist brush to touch it up. after all that go back over the screw heads with clear fingernail polish to help keep the shine.