Preventive conservation can be defined as all the measures and actions aimed at avoiding and minimizing future deterioration or loss of an object. These measures and actions are indirect – they do not interfere with the materials and structures of the items and they do not modify their appearance.
Preventive conservation was undertaken by the museum’s staff and volunteers as soon as the objects were excavated and handed over to the museum. Finds that underwent preventive conservation needed to be stored wet. When any waterlogged archaeological material is brought out of its marine environment, the effects of uncontrolled drying can sometimes be devastating. This is particularly the case for organic finds, as water often replaces the cells and components that the materials are originally comprised of. For example, leather finds can become brittle and split, iron can result in a potent corrosion reagent, and dissolved marine salts that have infiltrated porous stone and pottery can crystallize and cause cracking and splitting known as lamination.
Remedial conservation techniques can prevent this from happening when the objects undergo controlled drying but, until any remedial stabilization could be achieved, the objects were immersed in chilled water in airtight Stewart boxes. The staff and volunteers included a layer of bubble wrap (bubble-side down) on the surface of the water to exclude oxygen and sealed the containers with Parafilm to further ensure that the container remained airtight. The boxes were then labeled and stored in the cool, dark and humidity-controlled conditions of the archaeology stores until they could be taken to undergo remedial conservation with a Historic England conservator. Of course, all preventive work undertaken on the objects were recorded and finds underwent regular, recorded water changes and monitoring to ensure that they remained safe and stable.