Most of the time when you have a dedicated server, you could be colocation or you could have a managed server. Unfortunately, if you own the equipment or buy used equipment, there could a chance that there is proprietary data that could do damage to your company if you left it on there without properly disposing of it. One of the easiest ways to wipe a drive remotely on a *nix based system though is with the command shred.
If you have a console or terminal connection, then you can issue:
shred -f -z -v -u /dev/sda
This will basically wipe a drive instead of doing your normal deletions where the data could possibly be recovered. The shred command is covered more in depth but in essence it overwrites the deleted sectors with other data which essentially destroys the deleted sectors. Probably a good idea for any system administrator that is maintaining servers remotely with no way to access them the drives themselves physically.