Continuity mistake: At Dr. Jim's when he is standing by where the generator should be, you can see several items around. When it cuts all the items has moved. (00:22:40)
Continuity mistake: When the trailer is being dragged by the bulldozer, the wheels rotate. The trailer would need an air hookup to make it happen, otherwise, the tires won't rotate.
Continuity mistake: When Burt and Heather are fighting the graboid in their basement, shortly after Heather yells "Magazine!", one of the large revolvers between them falls off the rack but is replaced in the next shot.
Continuity mistake: When Val is getting the fuse lit on his bomb to throw to the last Graboid, we see his hands separated, one holding the bomb and one holding the rope. The camera angle changes to a close up of his hands, where they are now both holding both the bomb and rope. (01:24:50)
Continuity mistake: In the beginning of the movie, watch Kevin Bacon's hair when they're driving in the truck. In some camera shots, his hair is blowing in the wind. In others, his hair is not moving at all. This happens several times.
Continuity mistake: The green fuzzy dice in the guys' truck change over and over. Sometimes they're stuck up behind the rear view mirror, sometimes they're hanging down. Granted, they could fall and the guys could stick them back up again, but in one scene when they're behind the mirror, the faces of the dice that are visible from the front change.
Continuity mistake: When all pole vault, Fred is holding the pole in his right hand palm up. Then he goes 1/2 the distance and returns to the start but his right hand is palm down. (01:00:00)
Continuity mistake: When Val is climbing up the electrical tower to get Edgar down, at first the sky is blue, then suddenly it's overcast. (00:13:40)
Continuity mistake: After Burt reports on the radio that he has killed the graboid in his basement, there are shots of the towns people celebrating. The sky behind all of them is different, specifically the mother and her daughter. In other shots there is blue sky. In these shots there are darker clouds.
Continuity mistake: In the scene where Walter is being attacked by the Grabbloid, the blood coming from his nostrils, and blood on his upper lip, changes between the first and second shot. (00:51:20)
Continuity mistake: When Val, Earl and Rhonda are on the rock and decide to pole vault off, Rhonda's backpack is flat when she scrambles down the rock, but appears full once she reaches the bottom. (00:40:20)
Chosen answer: The machine is a vibrating case cleaner, which is used to polish the brass casings of pistol and rifle ammo. The "dirt" is actually an abrasive polishing compound.
BGraz