How to delete bookmarks on your Kindle
There are a couple of ways to delete the bookmarks on your Kindle reader: While the book is open on your Kindle 2, go to a bookmarked page. Touch the menu button. Click delete bookmark.
Or
While in the book, press Menu, go to My Notes and Mark“, then move the 5-way selector to what you want (up and down, don’t actually press to select it) and then press the delete key. This will remove not only bookmarks, but highlights and notes as well.