There are several easy ways to reduce the smell of memory foam. Airing it out will take care of most of the chemical smell, but you can clean it to further neutralize any odors that are still present after several days of air exposure. Memory foam was originally designed for the astronauts, but, due to the smell, has limited potential due to the way that air is circulated in those close corners; so use only in a ventilated area.
Fully open the memory mattress or topper and allow to breathe by unrolling it and setting it on the ground to flatten. The chemical smell becomes concentrated while the mattress or topper is encased and compressed. Air it out to allow the smell to dissipate and flatten out for use on your bed, futon or couch.
Spray the memory foam with a deodorizer to mask or neutralize the smell. Open the memory foam mattress or topper and spray the deodorizer, covering the entire surface. Allow the liquid to dry, then flip the memory foam over and repeat the process on the other side.
Place the memory foam outside to air-dry. Hang it on a clothesline or set it on a clean, flat surface with fresh-air exposure to allow the chemical smell to dissipate into the open air. Place in an area where the memory foam will not get wet or excessively dirty. Clean the memory foam before placing it on your bed.
Fill a water bottle with 1/2 cup of cold-water detergent and 1 cup of water. Shake the bottle to mix its contents. Spray the memory foam until it is damp. Let the foam sit for 30 to 45 minutes, then rinse the detergent and water mixture off using your shower or a garden hose.
Mix 1/4 cup vinegar and 3/4 water and spray the memory foam as in Step 4 to cover most of the foam. Rinse with water, then carefully squeeze out the excess water and use a hair dryer to completely dry before using on your bed.