If you have returned a book from Kindle Unlimited, there is no way to delete it from your history.
Yes, you can view your Kindle Unlimited history by going to “Manage Your Kindle” on your Kindle device or website.
To delete a Kindle unlimited list, open the Kindle app on your device and go to Manage Your Kindle. Tap the Books tab and select My Library. Next, tap the List name at the top of the My Library screen and select Delete List.
On your Kindle, go to Menu > Settings > Device Options. On the left side of the screen, under “Personal Document Storage,” tap on “Your Kindle.” Under “Manage Your Kindle Content,” select “All Items.” At the top of the list, select the book or item you want to delete and press the “Delete” button.
No, you do not have to return books on Kindle Unlimited. However, if you no longer want the book, you can delete it from your Kindle Unlimited library.
No, Kindle Unlimited books expire after a set amount of time.
You can borrow up to 10 books with Kindle Unlimited.