Cleaning your dishes daily with the same sponge will cause it to start to smell sour. This is due to the fact that sponges are porous and can trap food particles within these pores easily which will cause bacteria to grow much sooner. If you do not want to be smearing bacterial sour smell on your dishes, it is best to clean your sponges thoroughly and allow them to dry before using again. Removing the smell is great, but preventing it is even better!

The main thing to remember when cleaning with a sponge is that you do not want to leave bits of food within the pores once you are done cleaning. Remove any visible pieces then ring out the sponge under hot running water to get most of the food particles out of the sponge. This will help to keep the sponge cleaner longer. This will not totally prevent sour smelling sponge, but it will help keep it smelling cleaner longer.

Deep cleaning the sponge can be done in several ways. Using diluted bleach, you could allow the sponge to soak for several minutes to help reduce the amount of bacteria left on the sponge after washing dishes. You can even soak the sponge in white vinegar to help kill off bacteria and remove sour odors. For very deep cleaning, you can leave the sponge in the dishwasher within the utensil rack to be steam cleaned, which research shows kills off 99.99% of bacteria on your sponges.

Another process involves your microwave oven. If you are careful enough, after cleaning the sponge regularly when finished washing dishes, ring out most of the water within the sponge. Leave a little bit of water in the sponge to allow the microwave to steam and boil the bacteria to death. This should only be done for about 2 minutes on the highest setting but never more than 5 minutes. If you see any smoke or smell burning materials, you will want to stop the microwave immediately. Never attempt this method with sponges that contain metal! Always remove the sponge with some tongs or allow it to cool completely before touching it!

Allowing your sponge to dry after each deep cleaning method also allows fewer bacteria to multiply. This helps to prevent sour sponge smell and can keep a sponge useable for much longer than it would with minimal care. If a sponge smells too sour, it is best not to try and salvage it but to throw it away and start off fresh!