Metal （stainless steel, powder-coated steel, aluminum） is the preferred material for display cases and storage shelving or cupboards. It is strong, smooth, inert, non-flammable and does not emit any harmful vapors. However, to prevent rusting in situations with high humidity levels, it should always be covered with a protective layer, preferably a baked enamel finish rather than a paint.
Woods produce harmful vapors such as formic and acetic acid and peroxides, although some are worse than others. Freshly cut and unseasoned wood produces the greatest quantities of these vapors.
Composites, such as plywood, chipboard, particleboard, fibreboard, and masonite all could cause problems. Some MDF and plywood use a higher grade of adhesive that other composites and so is more stable if a wood composite must be used. It does however still emit some formaldehyde
The release of harmful vapors by wood and wood products is a normal chemical process that cannot be prevented entirely. The only way to minimize the emission of any harmful gases is to seal the wood with either a paint-on sealant or a barrier foil.
Many plastics off-gas over time and produce plasticizers that can damage certain materials. Plastics such as PVC, chlorinated rubbers, cellulose nitrate, cellulose acetate, or rubbers with sulfur vulcanizing agents should not be used because they contain chlorine and are a danger to the museum objects. Plexiglas, lucite, polyethylene, polypropylene, polyester, polystyrene, acrylic, and polycarbonate plastics are all safe to use.
Plastics such as Plexiglas and acrylic are a good choice as barriers to prevent visitors from touching objects on display. Vitrines made of these materials are useful for protecting objects from dust and airborne pollutants. Plexiglas and acrylic are also effective barriers for the security of objects from theft or physical damage.
Fabrics should be chosen carefully. Wool and all fabrics coated with fire retardants or finishes and foam or adhesive-backed fabrics have been found to give off harmful vapors and are therefore not recommended.
Undyed and unbleached cotton and linen fabrics are safe to use as long as they are thoroughly washed and rinsed prior to installation. The ideal fabrics for case design are those held together by thermal/spin bonding or needle punched. Textile surfaces should not have surfaces that can stick to the surface of the objects being displayed.
Glass is safe for use near museum objects. It is scratch-resistant, gas-impermeable and is available laminated or coated with UV-filters. Weight may be a disadvantage though, and its low surface temperature may cause condensation and mold growth on the glass and also on organic materials that become damp as a result of the condensation.