Goo Gone to clean the back side of the foil. Once clean, clean again with alcohol and let dry. Then a thin layer of rubber contact cement on both surfaces to be joined. Allow the contact cement to totally dry, then carefully position and press it on, smoothing it out. The contact cement must be allowed to dry before joining the pieces. Excess cement can be be rubbed off.
Might want to mask off the surface of the bell with blue painters tape to make placement of the cement and foil more perfect.