I have not attached an emblem to a shell (replated) for a long time, however I believe that first it must be checked to see the mounting circular part is undamaged, i.e. bentup or deformed. If the mounting part is OK, I think one needs to make sure the emblem is started straight into the shell. Once it is straight, I think the shell with the emblem started into the shell hole should be laid down on a smooth hard surface with a protecting material like outing or other soft material between it and the hard surface. Then using a plastic pipe that just surrounds the hole flange of the radiator shell, gently tap the shell down to seat the emblem. It might not hurt to place a little bonding agent on the back side of the emblem to ensure it doesn't fall off. This is just my thoughts on how to do it, so take it for what it is worth.
BTW, Tom Wesenberg sells a neat and cheap tool to easily and safely removes the emblems from shells. He removed the two emblems in the picture in the previous post in less than 3 minutes with no damage. His tool does not damage the mounting part of the emblem. Be sure, however, to catch the emblem before it falls on the floor once it pops out.
