If you find white residue on your shower, it is likely soap scum. Soap scum is a combination of dirt, grease, and soap that has built up on surfaces. To remove soap scum, you will need to use a cleaner that can break down the oils and dirt. There are many commercial cleaners available, or you can make your own with vinegar and water.
To clean with vinegar and water:
1. Mix equal parts vinegar and water in a spray bottle.
2. Spray the mixture onto the affected areas.
3. Let sit for several minutes before scrubbing with a sponge or brush.
4. Rinse well with water