Never use a screwdriver as a cold chisel, or for prying, punching, chiseling, scoring or scraping. Ensure that the tip fits the slot of the screw. If you use a screwdriver that is too large, you may damage the slot in the screw. Use a long-shanked screwdriver only for jobs in hard-to-reach places. For regular jobs, choose a short shank or ‘stubby’ screwdriver, as these will add extra strength. Choose screwdrivers which are slightly magnetised. These help to prevent slipping. Discard a screwdriver with a worn or broken handle or a chipped or worn tip. Never depend on a screwdriver handle or covered blade to insulate you from electricity. Switch off all appliances first before dismantling. When using a mains tester, test it on an item with less than mains voltage first to see if the insulation is secure.