Delete messages in service broker queue

I'd like to clear my queue in SQL Server Management Studio, but I don't want to delete the whole queue just the content in the queue (the messages).

Something like this should work:

while(1=1)
begin
    waitfor (
        receive top(1)
        conversation_group_id
        from dbo.yourQueue
    ), timeout 1000;

    if (@@rowcount = 0)
        break;
end