4 Grandma tips to recover opaque tiles

Another effective trick is to mix equal parts of water, baking soda and salt.
Mix well until you get a homogeneous mixture and pass it on the tiles, helping you with a sponge.
Rub well, then rinse with plenty of water.

Toothpaste to clean tiles

Toothpaste is one of the most effective products for whitening, especially those produced with baking soda.
Apply a little toothpaste on a sponge or a toothbrush and rub on the tiles.
Finally, rinse with plenty of cold water.