If the clay figures have been painted with ordinary oil paint it would be impossible to fire them, for the heat would immediately burn away the colours. Besides, the heat of an ordinary oven would have little effect on the clay except to dry it. To preserve modelled objects without casting, model them in plaster-of-Paris. A little glue added to the water when gauging the plaster will prevent it setting, with the result that the plaster may be handled like clay. Cream of tartar will also retard the setting properties of plaster. When quite hard, the modelled figure may be dipped in melted paraffin wax, so that it becomes susceptible of a high polish, and by the addition of certain pigments to the wax a colour may be imparted to the figure. For instance, a little yellow ochre will give the appearance of old ivory. Drapery may be represented by dipping strips of cloth in the plaster and arranging them on the figure. To judge the amount of size water to be used when gauging the plaster, dissolve some good glue in water and measure a certain quantity of this with a certain quantity of water. "With the mixture gauge a small quantity of plaster to discover how long the mixture takes to set.

Small clay models, if varnished, may be preserved for an indefinite time, but, being simply dry clay and not having been burnt, they are easily broken.