After you've sold your book, you can come back to SlugBooks to pause or remove the listing - to do this, make sure you have logged in at this link: http://www.slugbooks.com/listings.html

Once you are logged in, a "My Listings" menu item will appear which allows you to manage all of your active listings.

From this page you have the option to change the listed price of your book, delete your listing or repost to your Facebook timeline.