What can happen if soap is left on a sponge?

If soap is left on a sponge, it can lead to the growth of bacteria and mold, as the moisture and organic compounds in the soap provide a suitable environment for microbial development. Over time, the sponge may develop an unpleasant odor and become discolored. Additionally, the soap residue can make the sponge less effective for cleaning, as it may leave a film on surfaces rather than effectively removing dirt and grime. Regular rinsing and drying of the sponge can help prevent these issues.