[Developers] MQL "clearing" a unique property

[Dae Park]

Is there anyway to "clear" a unique property without knowing it's  
value? For example if I had:

{
   id: "#foo",
   type: "/my/type",
   bar: {
     value: "some value",
     type: "/type/text"
   }
}

and "bar" is unique, I basically want to do a connect: "delete"  
without having to specify the value I'm deleting.