Abstract: A method of preventing over ejection of material from a caulking canister of a caulking system having an ejection member passing through a body of the caulking system includes the steps of securing a female element to a moveable backplate of the caulking canister, securing a male element complemental to the female element to an end of the ejection member normally in contact with the moveable plate, and securing between the system body and an opposite end of the ejection member, after mutual securement of the male and female elements, spring to selectably urge the plate away from the caulking canister to cause within the canister a relative vacuum. The effect of such relative vacuum is to prevent over-ejection, also known as oozing, of caulking material from the dispensing nozzle of the caulking gun.