When a printer's roller is unfit for further use, all the composition is stripped from the iron or wooden core and is carefully washed in hot water, cut into small pieces, and soaked in cold water for about an hour. The composition may be re-melted repeatedly, but must be strengthened on each occasion by the addition of treacle and glue. Ordinary roller composition may be bought ready for use at about 8d. per pound; or it may be made by melting 21b. of good glue, and then adding 61b. of treacle and 1/2lb. of Paris white. These proportions are varied according to temperature and to suit particular kinds of work. In cold weather, and to produce softer rollers, use more treacle; in warm weather, and for harder rollers, use more glue. The glue, which should be clean and brittle, is soaked in water, which when the glue begins to swell is poured off; the glue is then placed in an inner vessel surrounded by an outer vessel holding the water, which must not be allowed to boil. AVhen the glue has been reduced to the consistency of syrup, add the other ingredients, and keep the mixture heated for about an hour, taking care that the glue is not allowed to become too thick.

The state of the composition should be tested by placing a little of it on a piece of paper; it, when cool, it is firm to the touch - that is, rubber-like rather than doughy - it is fit to be poured into the mould, which should have been previously warmed and oiled. The core of the roller, before being placed in position in the mould, must be perfectly clean and dry, or the composition will not cling to it. The composition must be poured in at one side of the mould, so that the air may escape at the other side. After the mould has been filled, it should be allowed to remain in a cool place for at least twelve hours, when the roller may be drawn.