New cases may be preferred, constructed of safe materials such as metal, plexiglass, or some sealed woods. Separating certain materials from the display section of an exhibition case by lining relevant surfaces with an impermeable barrier film will help protect items from damage. Any fabrics that line or decorate the case (e.g. polyester blend fabric), and any adhesives used in the process, should also be tested to determine any risk. Using internal buffers and pollutant absorbers, such as silica gel, activated carbon, or zeolite, is a good way to control relative humidity and pollutants. Buffers and absorbers should be placed out of sight, in the base or behind the backboard of a case. If the case is to be painted, it is recommended oil paints be avoided; acrylic or latex paint is preferable.