Before stone is cleaned, a suitable method has to be selected depending upon the type of stone and what is to be removed. Soiling processes and the analyses which should precede each cleaning operation are presented. Cleaning techniques are described at length: waterspray, ultrasonic waves, laser applied thermal energy, airbrasive, poultices, etc. Advantages and hazards of the various methods are considered. A distinction is made between buildings of artistic/historical value and those without; different cleaning methods can be considered accordingly. Specific problems encountered in cleaning stone are also presented; in some cases impregnation of the stone must be done before the stone can be cleaned. The cleaning methods are evaluated by various tests and analyses; the effect of different cleaning methods is illustrated.