You can speed up the process by airing out the mattress in a well-ventilated room. You can also try using a mattress protector or an air purifier to help eliminate the smell. If you have ever wondered why your mattress smells, it is likely due to the polyester fabric used in its construction. This fabric is treated with chemicals that can cause an unpleasant smell. To remove the smell, you can try airing out the mattress or using a mattress protector. You can also try sprinkling baking soda on the mattress and vacuuming it up after a few hours.