Castime was a modelling kit that you originally bought in a box. It contained a cardboard cylinder full of white powder, a few red rubber moulds, a small stand and some paints and varnish. You mixed the powder with water as instructed, then carefully poured it into one of the upturned moulds supported upside down on the stand. After a few hours it had hardened, and the rubber mould would be carefully peeled off to reveal a small statuette, typically about 3 inches high. It would then be painted in different colours and then varnished.
My sister and I would spend hours on this. We bought refills of the powder, not knowing enough at that age to work out that it was just plaster of Paris sold expensively. We made Father Christmases first, painted in red and white, of course, and with a brown or black sack over his shoulder. Then we made little Scottie dogs, usually painted grey. Most difficult of all were the Cinderellas. This was because when the rubber mould was peeled off, sometimes the head would snap off at the thin neck and remain in the mould. The broken ones had to be thrown out.
We sold them at pennies a time. Some went to family members, but our best customer was Mrs Outhwaite. She had been a childhood friend of my aunt, and was now a teacher at our primary school. She bought a couple of them every time she came, allegedly to pass on to friends, but in retrospect, probably just to encourage us. The pennies paid for the refills, and the activity brought months of pleasure. It was not all that creative, given that we bought ready-made rubber moulds, but it was quite delicate, especially in the painting, and we found it immensely satisfying to turn white powder into colourful statuettes.