If one of your favourite assets is faulty when downloaded from the DLS, you may wish to repair it and provide that repair to others. This may be particularly important for a content creator wishing to use that asset in their creation.
The Download Station Cleanup process allows a trainz user to repair assets created by other trainz content creators on the DLS. You can find some documentation about the process on the TrainzDev Wiki.
If you do decide to repair an asset, there are some things to bear in mind:
In the past, there have been some repairs uploaded which while they technically passed validation, there were still problems -- up to and including the entire asset being invisible. If you discover one of these, first check whether it is in the DLS repair list. If it is not in the DLS repair list, then contact the helpdesk, and log a ticket in the 'Planet Auran' section -- if Helpdesk agree the asset needs repair, they will add it to the DLS repair list so you can claim it and repair it.