a mechanical bag closure and sealing assembly which includes inner and outer elongated inter - engaging clamp members between which the upper edges of a bag are selectively compressed and sealed and wherein the inner member includes opposing wall segments which are compressible to reduce the effective cross section thereof upon application of pressure to opposing flanges extending on opposite sides thereof to thereby facilitate insertion and removal of the inner member with respect to the outer member . in alternate embodiments , the base of the outer member includes a channel for receiving indicia and / or for receiving a magnet for facilitating mounting of the assembly to metallic surfaces . in other embodiments , the assembly may be mounted within tracks secured to cabinets or walls .