Help: Failed to note set of discarded books

I discarded a couple of boxes of books. In the rush to clear out the boxes, I failed to remove the individual titles from my library or note they were no longer in the collection. Short of discarding the entire library and starting over, any suggestions to reconcile my list of owned titles. I thought to go through and make a take "Own" but if I search on that, I still would not know the titles not owned.

I cannot imagine I am the first to have done this.

You can go through and take inventory.
On the Your Books page, where you see Tags or Authors, you select the drop down and it offers a feature of take inventory. This would allow you to go through the books you have and note them as there. Then you can remove the titles you no longer own.

Of note: Any books deleted will also delete any comments, private comments, or reviews you've added to those books.

You can do the same thing by adding 'inventory status' to one of your styles. You should decide whether you want to delete the books you have discarded, or move them to a separate collection. I am finding that I do different things with different books depending on various things - books with ratings and/or reviews get marked as discarded. Old books that I don't remember and am unlikely to run into again get deleted.