40 g of CuCl2 are dissolved in 400 ml of 20% hydrochloric acid. 40 g of elemental copper (wire or shredded) are added and the solution is heated (on the water bath) until the previously dark brown-green solution has become almost colorless.
The (filtrated) solution is poured into cold water (I'd propose DI ice-water, about 2l), the white, precipitated CuCl is filtered off and washed frequently with cold water. Product should be sucked dry on a buechner funnel and dried in an evacuated dessicator over silica gel for best results.
[Translated from:
K.A. Hofmann: "Lehrbuch der Anorganischen Chemie"; 5 th ed., 1924, Verlag Fr. Vieweg und Sohn; italics mine]
Quidquid agis, prudenter agas et respice finem!