the prevention from hardening upon storage of paste - like material by use of a lid having an inlet port , an outlet port , and a plastic bag attached to the inlet port . by expelling the air in contact with the paste - like material , the material can be prevented from hardening during storage . a similar lid is used in a pre - cleaning device situated between a dust - producing tool and a wet / dry vacuum . dust - laden air enters the device through an inlet port and is discharged over a water filter . the pre - cleaned air is vacuumed to a wet / dry vacuum . the pre - cleaning process lengthens the useful life of the wet / dry vacuum . a hand - held sander is disclosed which provides for rapid change of sandpaper . the sander has a hollow upper handle component and a lower surface component which are held together with a latch . depressing of a quick - release button allows separation of the two parts .