The stoppering of bottles is an operation usually performed by the makers; it may, however, be useful to know that badly-fitting stoppers may be readily fitted by re-grinding; this is done by dipping the stopper in a mixture of fine sand, or still better, emery and water, replacing it, and turning it backwards and for wards with a slight pressure; fresh sand must be applied from time to time. When the fitting is exact, so that the stopper turns freely without shaking, the whole may be finished off by using a little fine emery and oil.