Get some plastic (so they won't rust) containers. such as For example, one gallon (here it's 4 litres) ice cream pails. You can even decorate them if you like.Fill them about half full with lime (calcium oxide), you can get this at your local lumber yard or hardware store. Place two or three of them (or more, depending on the size of the area to be covered) in unobtrusive locations in your basement. The lime absorbs the moisture and mildew, etc., along with the associated odors. It works!