Free screws and extra lives
When you start Plug Man's stage stop at the first pipe that the floating enemies spawn from and just keep killing those enemies. As you kill them they'll drop all the usual drops and some of those drops will be screws and extra lives, many more screws than extra lives. The supply seems to be indefinite but the computer might realize what your doing and slow the droprate of screws and lives ,However, it never completely stops dropping extra lives and screws.
Added by: Mike941 Sep 27th 2008, ID#3192