Cyclodextrins are cone shaped molecules that are made up of starch and sugar rings. Cyclodextrin molecules can be found in nature or artificially made by manipulating starch molecules. Cyclodextrins can be applied to cotton fibers to make cotton fabrics that absorb odors. Odor molecules such as butane and propane are the most commonly attracted. The center of cyclodextrins absorbs the odor molecules of certain shapes and sizes making it difficult in some cases for the cyclodextrin structures to effectively absorb the full spectrum of odor molecules. If an odor molecule is too big or too small for the structure, they can either bounce off or pass right through the cyclodextrin structure.