They are rollback related, the DBA should be taking care of these proper.
If they go away, Oracle might Shit itself.
Usually, you devote a big chunk of disk each to: the DB, the Rollback and the Archive Logs
Only a Hundred MB ea? Either you have a VERY small DB or a TON of these files or Dam, you must not care about problems and restoring from points.
I'd suggest you have a REAL DBA look at the settings for the DB.