Recently found a book that is practically a collection of "how not to's." It's a Pentateuch printed in 1859 in Germany, and it has issues starting right from the title page and throughout the book.
Paper Repair and Restoration
Washi is often dubbed “the world’s thinnest paper,”. Chinzei’s variety, tengu-joshi washi, is 0.02 millimeters thick and weighs 1.6 grams per square meter. As opposed to standard paper, which is thicker and weighs 70 grams per square meter.
One of my most exciting projects was an 18th-century book I worked on for one of my restoration course final exams. The book was brought to me by a friend, and its story started to unveil as the months went by.