Question: I would like to know if can delete the bids?
Answer #1: Yes! Go into your Admin Center. On the left hand side (on your menu), expand "Pilot's & Groups". Next, click on the link that says "View Bids". Delete the bid(s) you no longer want in there.
Answer #2: If you are wanting them to expire after a certain amount of time, you will need to go into your local.config to correct that setting.