Biodegradable Odor Interceptor from Del Vel Chem Co. is used to neutralize and absorb odors from a variety of sources. It lasts 45 to 60 days, depending on the degree of odor. The product shrinks as it absorbs odors. The heavier the odor, the faster it is used. It will shrink to about 12 percent of its initial size before it should be replaced. Once odors are under control, it will shrink at a slower rate. It is available in 1/2-, 4- and 35-pound containers. 800/699-9903; www.delvel.com.