An approximately 1" wide strip of the inside surface of each board is cleaned down to bare board at the spine edges. This is normally a simple matter of scoring a line with a knife and straight-edge and lifting the paste-down with a microspatula. Care is taken to avoid cutting clear through the turn-ins when scoring the boundary line and to avoid tearing them when scraping the paper from them. But despite the utmost of care, sometimes the turn-in will lift and thus will need to be tacked back down with PVA mixture. All this is assuming that the original cover material is cloth. If it is paper, it is sometimes best to make no attempt to remove the old paste-down from it.
Card pockets, book plates, and such are removed from the inner surfaces of the boards, usually by lifting them out with a microspatula. If a book plate is glued solid and is tight, only the part of it overlapping the 1" margin of bare board needs to be removed. However, it will usually show through the new paste-down, so if this is a concern it all needs to be removed.
If the book is from a collection that uses security/detection strips and there is no evidence of one on the inside of the case's spine, it is at this time that a strip is attached at this location.
