Abstract: In batch transport of waxy crude and refined-products through a pipeline, a special difficulty is contamination of the product by the wax deposit on the pipe wall. The dissolving and eroding effect of the flowing product stream on the wax deposit are experimentally studied, and the effect of wax-deposit addition on quality of the diesel ^#0 are examined. On this basis, a technical scheme is proposed to diminish contamination of refined products by the wax deposit, i. e., in order to clean the wax deposit on the pipe wall, pigging is necessary nearly at the end of a crude batch.