Grinding compound keeps screwdriver in the slot

While trying to remove a screw that just won't budge, you twist the screwdriver even harder. The sides of the blade ride right up the sides of the slot and pop out—a phenomenon technical types call "camming out," and which you call a major irritation. Solve the problem with a can of valve-grinding compound, an abrasive powder suspended in oil. (Auto-parts stores sell it.) Dip the end of the screwdriver into the compound. The abrasive particles between the screwdriver blade and the screw slot prevent cam-out, so you can put more oomph on the screwdriver to break that stubborn fastener loose.
—Gordon Reiter, Ridgeway, Pa.