ABSTRACT
It was noticed that many of the Tutu ceramic sherds were coated with “insoluble salts” (calcium carbonate) which needed to be removed in order to expose any decoration beneath and catalogue the sherds. When a certain type of redpainted sherd was placed in water, the red color seemed to float out into the water and dissipate. Noting Roosevelt’s (1991: 349) observations that, at the Marajoara site in Brazil, “we were able to find traces of water-soluble polychrome paint on many sherds that would have been classified as plain or simply white slipped if they had been washed” and that a former practice of scrubbing pottery had greatly reduced the frequency of decorated pottery in some assemblages,; the current author wished to avoid similar loss. To solve the problem, the author met with Virginia Greene, Senior Conservator at the University of Pennsylvania Museum, to seek her advice. In a letter to the author (personal communication, May 18 1992), Dr Greene indicated that some pots probably had been red slipped after they were fired. She found that, while not actually “water-soluble,” the slip tended to come off in water as a result of physical action. Dr Greene indicated that “since you can not tell in advance which sherds have this coating, it will be necessary to clean all sherds without rubbing or excessive action.” Sherds with incrustations would “have to be cleaned in acid and then soaked in water to remove all traces of the acid, which can later do a lot of damage inside the sherds.” Dr Greene then provided a detailed procedure for cleaning the Tutu sherds without removing the fragile exterior slip and these instructions were carefully followed.
