Clean space on my private OBS instance

Hello, I am managing an OBS instance for my company, and i'm running into a problem. Some service started to crash because of the fact that all the disk space was used. After a "du -h", I realized that all the project that existed on my OBS still left leftovers, consuming space. Does a magic trick exist to wipe out all those artifacts from the past to gain some disk space ? Thanks a lot in advance Thomas HERVE