A set of gilt leather wallhangings, belonging to the Rijksmuseum, were dated to around 1660. Since their acquisition in 1946 several applications of oil/grease had been given, more than is nowadays considered necessary. The procedure whereby this fat was removed, then replaced with the correct amount, is described. The precautions necessary when dealing with organic solvents are explained and the equipment described. The fat dressing applied is 8% neats' foot oil, 2% imidizole as buffer and 6% isopropanol in which the buffer is dissolved. White spirit makes up the mixture which needs to be continually shaken since the lanoline sinks to the bottom. Four applications were necessary in order to introduce the required amount of dressing (3% by weight) to the leather. Photograph, diagram.