Pest insects pose a continuous and serious threat to museum objects that are organic in origin. Traditionally various chemical substances have been used for insect control, but in recent decades there has been increased concern about the disadvantages of this type of control strategy (Dawson 1988). Among the alternative control methods developed for museum use in recent decades, low oxygen treatment (Gilberg 1991)is of special interest. Using nitrogen or argon to replace oxygen, produces no residues and allows a conditioning of the gas regarding temperature and relative humidity. The first practical application in the Nordic countries of this method took place at Skokloster Castle in Central Sweden.