Re-apply, scrubbing with a soft bristled brush, if necessary. After the basement area has been cleaned and disinfected, you should be able to pinpoint the source of the odor. Once you've located where the odor is coming from, you'll need to identify what type of odor problem you have. Mildew commonly occurs in carpeting, on walls, around doors and windows, and in bathroom and laundry areas. Cut an onion in half and place it on a plate on the basement floor.
Onions work great at absorbing mold and mildew smells.
Two slices of bread placed on a dish in the basement overnight will absorb smoke smells, mildew, stale air and animal odor. Place a dish of it on the floor or hang it from a bag year round to help keep your lower level odor-free. Millions swear by the power of common household baking soda. Simply open container and place out of sight in the basement for up to three months at a time. Baking soda can also be applied directly to stubborn smells and problem areas.