Currently there is no way for members, except torrent staff, to promote (recycle) torrents.
There is since my earlier post added to the site's system an "auto recycler". It promotes old torrents, following a complex algorithm with a random component at a limited pace.
Staff uses the promotion for various reasons, e.g. an original with only 1 or 2 seeds in a duplicate report, testing if really dead before deleting, helping members to get it downloaded, helping members with ratio (torrents only seed by them), etc… but as there were complaints about too many promoted in the list, these cases are limited.