Even today, in Poland, some cemetery plots are rented for only 40 years and then the bones are placed into storage. They also bury one coffin on top of another until a grave is full to maximize the space. Bones headed for a charnel house were handled in different ways. Sometimes they were cleaned and sorted by type of bone, bundled and stacked. One person also reports that the bones might have been used for weapons and medicine, although I have not been able to verify that.
Charnel houses are quite the tourist attraction.
If you would like to read about one charnel house, visit this article about The Bone Church . Some Native Americans also used charnel houses. Read about the burial customs of the Choctaws before the 1800's . So it was when bones were being moved to the charnel houses in England during the 19th century that some coffins were discovered to have scratches on the inside, indicating that these persons might have been buried alive. Shakespeare's curse did have its desired effect.