Prevention is always better than cure in conservation as well as medicine. Instruments will remain free of rust or other corrosion products indefinitely if cleaned thoroughly after use and stored in a dry atmosphere. Suitably inert materials for storage containers are glass, polypropylene or Mylar and a small bag of silica gel will keep the contents dry.
Where instruments are already rusted they can be treated physically or chemically. Polishing with a very mildly abrasive wadding such as Never Dull is the preferred option in many cases but more abrasive cleaners should be avoided. Chemical treatments such as tannic acid, phosphoric acid and commercial preparations like Kephos are all possibilities. However many instruments pose complex challenges, particularly where coated with nickel or chromium, and in these cases a professional conservator should be consulted.
|Illuminating tongue depressor, illustrated in Elliotts and Australian Drug Limited catalogue 1934||Robin Massett's abdominal retractor, illustrated in Elliotts and Australian Drug Limited catalogue 1934|
Where it is impractical to store instruments in a dry atmosphere, or where newly cleaned instruments are particularly susceptible to corrosion, a number of surface treatments are possible. Coating with microcrystalline wax is a preferred option as it is an easily reversible process which allows different or additional treatment in the future. Various protective lacquers are also available and vapour phase inhibitors (VPI ) in the form of papers or tablets are another possibility. However the papers should be used with care as they often contain an oily medium which can attack organic materials such as felt lined boxes.
In general it is better to devote some time and effort to ensuring a good storage environment for your instruments in the first place rather than having to treat them later.
Roger Paris and Graham Clegg
Conservation Department Powerhouse Museum, Sydney