Clean it and spray a mixture of (colorless) vinegar and citrus juice on it. Vinegar dries out (smells only for a few hours) and mold hates sour. And if you have it in the bath, i had success with scrubbing the … joints (? german “Fugen”) with citrus juice and salt and soap (must be dry before). Washing shower curtain and carpet with vinegar helps too if they got it, doesn’t smell.