So you need to get rid of it as soon as possible! We'll tell you about proven methods.
The first cleaning method involves using hydrogen peroxide. First, you need to moisten cotton pads or paper towels with hydrogen peroxide. Then apply them to the contaminated seams so that there are no air gaps. Leave the pads for 24 hours, periodically moistening them if they dry out. After that, you should carefully remove the pads, go over the seams with a brush and treat them with undiluted vinegar. There is no need to rinse the vinegar. Let the seams dry, and you will see a significant improvement.
The second method is to use regular 9% vinegar. Apply it to cotton pads or towels, apply to the seams and leave for half an hour. After that, use a brush to thoroughly clean the seams. If the seams are colored, be careful, as vinegar can damage their color. Finally, wipe the tiles with a damp cloth to remove any remaining dirt, and let the seams dry.

The third method involves using oxygen bleach. Mix a tablespoon of bleach with warm water, apply the solution to the seams using a spray bottle or brush. Leave the mixture for 10 minutes, then thoroughly clean the seams with a brush. If the seams are very dirty, you can make a thicker paste of bleach and water and apply it to the seams. After cleaning, rinse off the bleach residue with a damp cloth, and treat the seams with vinegar.
The last, fourth method combines several components: hydrogen peroxide, vinegar, water and boric acid. Mix 50 ml of water, 25 ml of hydrogen peroxide, 25 ml of vinegar and 12,5 ml of boric acid. Heat the solution to 50-70°C, apply it to the seams with a brush and leave for 10-15 minutes. Then treat the seams with undiluted vinegar and let them dry. This method is effective even for old stains.
To prevent mold growth, we recommend airing out the bathroom after each shower, turning on an exhaust fan or opening a window for an hour. The tiles and shower enclosure can be wiped dry after use. Avoid leaving wet towels or shampoo bottles in the corners of the bathroom, as this encourages mold growth.