The big problem with shower walls is not dirt, but limescale that accumulates over time. To identify limescale deposits, you will notice white or dull spots that do not disappear. This includes the tiles, the shower fitting, and the bathtub.
To remove these limescale spots, opt for ammonia. Also very popular for domestic care, it is an excellent cleaning and disinfecting agent that frees you from all encrusted stains and yellowed enamel.
Put 2 glasses of ammonia and 2 cups of hot water in a spray bottle. Shake it and spray it on all calcified parts. Then let the product act for 5 to 10 minutes before rubbing it off with a cloth or sponge. Finally, rinse thoroughly with cold water. Here too, make sure the windows and door are open to eliminate the quite strong ammonia smell.