This bathroom equipment is sensitive to moisture and limestone. And for good reason: it tends to blacken because of mould. To give it a second life, arm yourself with water to which you add soap. Before proceeding with this technique, it is imperative to remove the curtain and rub it with a sponge. If the curtain is very dirty, use the famous white vinegar and put it in the machine that you will switch on to 30 degrees.
For the bathtub:

White vinegar will always be part of your bathtub. Simply add sodium bicarbonate and water. Once this mixture is ready, dip a wet toilet glove that you will use to clean the bathtub. Say goodbye to stubborn spots. If you are in a hurry, arm yourself with a spray bottle filled with this essential domestic acid solution.