the present invention provides a method and device for preventing the formation of deposits in a drainage system . the device includes a container , connected by a flexible cord to a stopper . an antimicrobial composition is placed in the container and the container is inserted into a drain opening . the container moves to the bottom of the trap of the drainage system . the container is preferably located at least partially beneath the water or drainage fluid in the bottom of the trap . the cord and stopper prevent the container from moving beyond the trap . the cord and stopper allow for removal of the container from the drainage system , once the composition has been fully dispensed .