An odor emission often consists of a complex mixture of many odorous compounds. Firstly, it affects apocrine sweat glands by reducing secretion of odorous molecules and its precursors. The odorous secretions produced by American cockroaches can alter the flavor of food. Scented sachets are for containing odorous substances to be laid among handkerchiefs to perfume them. Activated carbon an adsorbent, used for the adsorption of odorous compounds. Civetone is a macrocyclic ketone and the main odorous constituent of civet oil. Phthalates were first introduced in the 1920s and quickly replaced the volatile and odorous camphor. The most odorous chemicals in cigar smoke are pyridines. Some birds and toads will eat odorous house ants on occasion. Deodorization of DMSO is achieved by removing the odorous impurities it contains. This reaction is used to destroy odorous isocyanide mixtures. Flypaper is often impregnated with a slightly odorous chemical to attract more flies. That is when it sprays its odorous excretion. Along with pyrazines, they are also the most odorous chemicals in cigar smokers' breath. The olfactory system does not interpret a single compound, but instead the whole odorous mix.