I find that magnetic tipped tools attract a lot of metal shavings that I object to. However, every once in a while we all need a magnetic-tipped tool. For short term applications, just stick a magnet to the shank of the screw driver – it will extend the magnetic field through the screw driver. Simply removing the magnet will return the tool to its original state.
Depending on the steel used in the tool, repeatedly stroking the tool in one direction against a magnet can magnetize the tool. To de-magnetize a tool, just strike it severely against a hard surface such as a vise.
Induction coils can be used to both magnetize and de-magnetize tools on a larger scale or for more permanent results.