The present method of handling spark plugs in the Air Service is unsatisfactory on account of the very short life obtained from each plug. The average plug life obtained in service is only a fraction of that known to be possible from an average set of plugs and the difference is entirely attributable to the loss incurred when making replacements. The Engineering Division undertook the development of a simple and satisfactory method and also the necessary equipment for cleaning and testing spark plugs in large quantities. The procedure outlined insures that the plugs removed from the engines will be returned to the shop for reconditioning and that the plugs when reconditioned will be practically as good as new ones. The method and description of the equipment have been given in detail in order that this report may be made the basis for a Technical Order or an instruction manual on the cleaning of spark plugs.