Deuteronomy 12:4 "This you shall not do to the L-rd your G‑d"

This Negative Mitzvah tells us that we are forbidden to destroy or damage a synagogue or Yeshivah. We are also not allowed to damage a sefer, or to erase any one of the sacred names of HaShem that appear in writing.

All old sefarim and books (even school notebooks!), that have the name of HaShem in them or have notes from learning Torah, may not be thrown out in the garbage.

They are called "Shaimot" and must be given to the "Genizah" which may be found in Yeshivot or Synagogues. These books are then buried in a special place.