The easiest way to "reset" the MOTS is to reinstall the Beosound software, then it will reset all the indexes. This is better than deleting all the music. You will have to use the service menu on the Beosound to do this.
How do you do this?
A somewhat belated question but I rediscovered this thread from some months ago because MOTS is increasingly annoying me. Did B&O actually test this software properly? It really seems a bit repetitive after heavy use - always reverts to a few select artists or albums after a time regardless of the seed. I wish it had a random function or more control over the parameters for selection. Apple Genius appears to function better.