Clay is stabilized in the drilling of wells for hydrocarbon production by the addition to the drilling fluid of potassium formate together with an amount of guar effective to inhibit clay and shale swelling and sloughing. Slurry from the chemical mechanical polishing process is prevented from penetrating the impermeable transparent sheet to the bottom layer of the polishing pad. The detector is used to manipulate the set of data packets or create a record of data associated with the set of data packets.