Automatically delete old drafts

Fellow sufferers

How do I automatically delete all drafts, once there is a new approved version?

Example. Following versions exist: 0.1, 0.2, 0.3, 0.4, 0.5, 1.0, 1.1, 1.2, 1.3. Only 1.0 is Approved. I want Sharepoint to automatically discard 0.1,,,0.5, because 1.0 was published.

Thank you, you are great if you can answer this one!!!

Have a nice day.

Peter Hansen