Use an old, used toothbrush: not only is it easy to handle, but it can also reach places that would otherwise be difficult to reach. Spread a little toothpaste, rub it over the entire surface, insisting if necessary. You should make circular movements exactly like you do when brushing your teeth. Leave on for around twenty minutes, then dry with a soft, slightly damp cloth to remove the excess.
If a first layer is not enough, repeat adding the tip of a teaspoon of baking soda. This way you will enhance the whitening power of the toothpaste. The slightly abrasive action of baking soda will penetrate between the polymers and turn your objects snow white.
