Abstract: The present invention provides an adapter for use inconjunction with a paint can having an opening at one end and an inwardly extending rim adjacent the open end of the can. A continuous groove is provided around the rim and this groove has a preset width and a preset depth. The adapter includes an annular body which is dimensioned to be insertable into the can groove and to form a seal between the adapter and the paint can rim. The precise dimension of the body may vary between different can manufacturers. An annular channel is provided around an outwardly facing side of the body and this channel is adapted to receive and sealing engage a sealing flange on a standardized lid for the can.