We've managed to finish the bookcase cleanup despite lots of unannounced visits. We got rid of 250 lbs of training material from my mom's professional association. Those we're using one full unit (we have 10 units). Two others unit were holding all our reference book. We got rid of most of them, keeping the equivalent of two shelves of book we actually use (dictionaries,cooking books, etc...). Then my mom's decided to get rid of all her stuff (pamphlet, maps and others books) from her trip to Europe in 1975. She kept her travel diary, a bag of money from the country she visited and the picture album from the trip. That cleared another shelf. We also have 300+ book to give away (a nice collection of geographic book is going to my boyfriend who asked for them, we offer the rest to family member and friends, what they won't take we will try to trade to the used bookstore and the rest will go to goodwill). We then cleared the top of the bookcases of all the randoms knick-knacks. We kept the most meaningful and got rid of two glass jar, five stuffed animals, another oil lamp and three unidentified trophies. A family friend took a big box full of frame for his painting class.
So now, all our book are in a proper upright position, not stacked one upon another and they are not all squeezed together . We have one unit empty and the other one is temporarily holding the books we are getting rid off. One of the now empty unit will be used to display my mother's frog collection (no no, not real ones) that is stored in the garage attic and the other unit will be used to hold my parents CD's and the books we borrowed from friends and family (some of them live far away and we see them maybe 2-3 times a year).
Cleaning the bookcase was the last step of the ''getting rid of stuff we inherited'' that came with my mom's being the last member on her family side. We got stuff from her parents and three aunts (two full households) in a very short period of time. It took us five years but we finally managed it and gain back precious space in our house.