To do so, use the --empty-attic parameter (see above).
Another option is to create a 'Greyhole Attic' Samba share.
More details about that here: httphttps://greyhole.pommepausegithub.com/docgboudreau/Greyhole/wiki/atticAboutTrash
= Reference =
Good [http://revxatlarge.blogspot.com/2011/04/restoring-deleted-files-in-greyhole-and.html article] on Greyhole with terms explained.