Changing a torrents label with Web API

[Rodent2008]

I have a question about changing the label of a torrent.

 

I am using the web api as documented and am able to add a label to a torrent fine.

 

CHANGING LABELS:
http://[iP]:[PORT]/gui/?action=setprops&hash=[TORRENT HASH]&s=label&v=[VALUE]
This action is specially documented because the label isn't returned in getprops (so changing labels is not obvious).

 

My question is how do I remove a label from a torrent, I thought it mite have been a toggle, run the same command again and the label would be unticked but no.

 

Can anyone shed some light please.

 

Regards

Rodney