Fill your bathroom sink three-quarters full with hot water.
Add a tbsp. of bleach to the water.
Drop the filter pad cartridge into the hot bleach water. Let it sit for 20 to 30 minutes.
Drain the sink and then turn the hot water on again. Let it run through the filter as it flushes the excess debris and remaining bleach water from the pad. Squeeze it a little bit as the hot water runs through.
Sit the pad cartridge on a rag and let it air dry for 30 minutes. Reinsert it back into the filtration system. It will last about a month before you need to replace it with a new one.