LMP, good advice as always from the guys above.
You might like to take a look at a similar question from about 3 months back.
The link will take you straight to a post about CHISELS!
, which is NOT as daft as it sounds! Some methods end up breaking the magnet and you might not care (most people don't), but if you do, then take a look see. The whole thread is worth a good read - there is tons of interesting and useful information there.
(Thinks . . .'there IS' or 'there ARE' tons? Ah the hell with it - it's interesting anyway!)