Abstract: A caulk cartridge cap is designed to enable the storage of unused portions of products of the types supplied within caulk cartridge type containers to thus maintain them in a reusable condition. The cap operates as a closure for purposes of resealing a caulk type cartridge to prevent the premature drying out or aging of the materials stored within the cartridge and to also prevent blockage within the cartridge applicator tube. The cap includes an orifice retention rod which is positionable within the applicator tube, and a self-threading insert positioned within the cap is then used to threadably attach the cap to the cartridge. Modified embodiments of the cap include the use of a tether, a scraping edge formed on the orifice retention rod, and a bracket assembly to which the cap is rotatably attached and which may be mounted to a conventional caulk cartridge holding gun.