A rattle to hang on the crib or even outside the doors!
Get plenty of empty cans to wash and decorate as you like. Make holes in them and pass a hemp thread or a strong rope through them and hang them from a support that you can then place wherever you want: The whisper of the wind will make them touch and play.
If you are even more skilled and experienced with crafts, you can also use tuna cans to make a wall clock. In this case, you will also need a handle mechanism that you can attach to the empty can after carefully drilling holes where necessary. So you see how many cute ideas you can come up with just by putting away the empty tuna cans ?