Up until this point, your dog has been searching for your glove or your sock.  However, as they become more advanced, they can learn to alert on a cotton ball with your scent.  The AKC novice searches use your sock in a line of boxes, while all the searches at the higher levels use a cotton ball.  It is often taped under an object in the room.  Like the box searches, there is not much time at all for the search to age.  

Teaching your dog to search for the cotton ball (CB) is not hard.  The first step is to scent the CB.  I just put a few in the jar with the glove and the glove will scent the cotton balls.  Before Iona searches, I do re-scent them by rubbing them on me, but this is not really needed if they have been in your stink jar for a while.  

It is important that your dog knows that they will be running HD searches and not oil searches, so start with a few searches using your glove to warm up.  I use clips with magnets on the back for my CB searches.  These prevent the dog from getting the CB in their mouth but let odor escape.  They are also easy to stick everywhere.  Make the first few searches with the CB easy and mark quickly to prevent frustration. I actually bring the magnet clip to trials and run Iona on HD searches right before her real search so that she is all ready to go!  It works well.