If you leave soap scum for too long, then it can become concrete and impossible to remove.
View How To Remove Heavy Soap Scum From Bathtub
PNG. If you have discovered really heavy soap scum, you can actually use a wet pumice stone to carefully remove. Remove soap scum—once and for all.
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You do not need to scrub and scour to remove the soap scum or water stains, because when left to do it's job, scum off will break apart the build up for. Remove soap scum effectively without commercial chemicals. The scum will continue to build until you take the time to remove it.
If you can't scrub it clean, you may need to just have the tile regrouted.
What's best for cleaning tile & grout. If you have a shower curtain rather than a door, you will probably have soap scum is caused by hard water, bar soap, and ineffective rinsing of the shower area after use. These examples show how to do it right. Because of how the cleaner works, it does all of the hard stuff for you.