exposed to volatile organic acids. Vulnerable silver objects should be stored in enclosures either with activated charcoal or in silvercloth, “which acts as sulphur scavengers." Silver objects can also be coated, or lacquered, with a clear barrier material such as Agateen No. 27 (cellulose nitrate) or Paraloid B-72 to prevent tarnishing, but these coatings require periodic reapplication. In order to avoid the presence of volatile organic acids, vulnerable objects should not be stored on wooden shelves or in wooden boxes. Sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3) are some of the most common types of gaseous pollutants found within collections and can result in the catalyzation of deleterious chemical reactions. The chemical reactions caused by these gases can result in the breakdown of inorganic and organic materials, or the tarnishing of metal objects. Other objects contain intrinsic elements that may begin to break down over time causing a damaging condition known as off-gassing. The storage of construction materials and basic housekeeping within a collection area may also be a source of gaseous pollutants. The hazardous fumes given off by strong cleaning products such as bleach or ammonia can transfer to objects causing deterioration, and construction materials such as adhesives, paints, and sealants may off-gas resulting in additional damages. Storage and display cases should be carefully evaluated for off-gassing risks, and following storage procedures such as those outlined above will all reduce the risk of contaminant damage to objects. Other sources of volatile organic compounds include collection objects themselves, such as plastics with short lifespans. Cellulose nitrate, cellulose acetate, and poly(vinyl chloride) are known to off-gas pollutants over time, and should be stored separately from other collections to decrease the risk of exposure. Adsorbents such as zeolites, silica or activated charcoal can be used in storage environments to decrease the concentration of acidic gases, but require continued maintenance. Tea leaves have been investigated as alternative sustainable adsorbents for cellulose acetate film collections. Liquid pollutants Human interaction with objects poses a threat of accidental contamination. Moisture and oils from human skin can cause staining of organic materials and corrosion of metals. This risk can be mitigated through implemented handling protocols such as washing hands and wearing protective gloves to minimize direct contact. Objects may also be enclosed in protective casing to further reduce direct handling when possible. Proper storage techniques, such as the use of neutral tissue or untreated cotton