Pare che fetchmail non supporti questa possibilita'
G5. I want to make fetchmail remove kept mail after some days.
The second-most-requested feature for fetchmail, after content-based filtering, is the ability to have it remove messages from a maildrop after N days, typically to be used with the keep option. Several messaging programs with graphical user interface support this feature.
This feature is not yet implemented. It may be at a future date, spare time of developers permitting.
For the time being, the contrib/ directory contains some unsupported tools that may help, namely mold-remover.py and delete-later.
Ma dove sarebbe sta dir contrib/? Non la trovo.