Addition by customer Linda Teders, Purmerend (Netherlands):
I used the side of my fridge for hanging up tea caddies with magnetic discs.
Contrary to the application above, I wanted a solution where I can attach the magnets to the outside of the caddies.
I wanted to stay away from glue, in case I needed to use the tin cans for something else.
Finally, I came across these small magnetic discs that can be easily attached and removed.