 Bynesian decay usually starts when specimens are stored or displayed for considerable periods of time in an enclosed space . The storage method itself usually causes this problem , when containers , cabinets or display cases are entirely or partially made of wood , plywood or other wood products such as <unk> , or when the specimens are surrounded by , or in contact with , various other kinds of materials that are cellulose @-@ based and can turn water vapor acidic . 
