How do I mark my Offer post and/or items as taken?
Go to the Your Posts page and click on the Offer post that contains the item(s) that you want to mark as taken. Click the button or link labelled "Mark as Taken" that is below the post title and fill out and submit the form. This will remove your old Offer post from the group listings.
If you're using the website (and not one of the apps) and if you offered multiple items in one Offer post and only one or two of the items have been taken, you should instead go to the New Post page and submit a Taken post that only lists the items that were taken in the item description and details fields.
Note: Even after marking an item as taken, you may continue to get emails about it because often people read the Offers in their email and don't check if an Offer is taken before replying to the email.