Chemically-enhanced centrifuging, CEC, is a drill site environmental control process for drilling mud. The process makes use of mud dewaterability for recycling the mud liquid phase and minimizing volume of the waste mud discharge. In this process, mud is chemically conditioned to enhance dewaterability-the ability of drilling fluid to release its liquid phase. This paper introduces a simple method, the nine-point (9-P) experiment, for finding optimum-chemical conditioning (i.e., combination of dilution water, coagulant and flocculent) that would maximize the mud volume reduction and minimize the cost of chemicals. The 9-P experiment is based on the statistical theory of factorial analysis and requires only nine tests to find optimum treatment. The paper explains how to design the experiment and analyse its results. Also presented is a comparison of 9-P (in terms of volume reduction) with the conventional trial-and-error approach. The comparison shows a significant, from 1.78 to 2.35-fold increase of the volume reduction efficiency, E-VR, and up to 3.7-fold reduction of chemical usage resulting from optimal selection of the most active flocculent.