Remo: You may or may not know this, but in the top right of the filter bar (beside the colour bar and under the lock icon) in the Library module are three icons for Master Photos, Virtual Copies and Videos. Clicking on the Virtual Copies will only show virtual copies in the Grid. Now, let's say you have four virtual copies of each image, and you only want to keep one (if you don't want any, just Select All and Delete). Adjust the zoom level of the Grid so that it's four images wide. You should now have all of the copies for each Master Photo in one row. Select the Painter tool and set it to Paint Rejected Flags. Now put the can over the VC in column 2, hold down the mouse and paint down. Ditto for column 3 and 4. Now that all of the 'extra' copies have been rejected, you can delete them easily enough.
Mike.