Samples of waterlogged leather from the Batavia were analyzed by x-ray diffraction and electron microprobe and shown to contain iron, sulphur and oxygen as the major contaminating elements in the form of alpha -- FeO (OH) and FeS (possibly as pyrrhotite). Hydrolysis experiments under controlled conditions showed that breakdown of such leather depends on the environment while under water and particularly on the stability of that environment. Attempts to remove all the iron as the thiocyanate complex in dipolar aprotic solvent systems were only partially successful because of dimensional changes produced by the treatment, however, a combined treatment could be possible where all the iron is removed and stability maintained by elimination of rehumidification steps and making use of dipolar aprotic solvent systems throughout.