Abstract: A cap for a caulking cartridge of the type having an elongated dispensing spout extending generally coaxially outward from one end thereof. The cap includes a spout receiver which, when the cap is in position, closely embraces a portion of the elongated spout to prevent undesired emission and hardening of the caulking or the like compound during cartridge storage between uses. The cap also includes a resilient u-shaped bead receiver for closely engaging the end of the caulking cartridge adjacent the dispensing spout and structure releasing the cap from its engaging position. The releasing structure may also be used for conveniently hanging the cartridge during storage. The cap is dimensioned so at least the outermost end may be received in another, substantially identical cartridge at the opposite end from its dispensing end for ease of packing, shipping and shelf storage purposes as to a substantial number of the cartridges having the caps. A forming blade may be attached to the side of the cap.