Well...I know that in the large monasteries in the old countries, they often exhume the monks' bodies and put all the bones in a separate chamber (ossuary). There simply isn't enough land to keep all those bodies buried separately for centuries. I think they inscribe the names on the skulls. In fact, there was an article in The Orthodox Word a couple of years ago about miraculous relics that were found when they were moving all the bones from one ossuary to another in Greece. They discovered nine skulls that were streaming myrrh.
That being said, what you described (baggies) sounds a bit more offensive and grim, to me anyway.
This. If you've seen the new film, The Mysteries of the Jesus Prayer
(and I do recommend it!) Fr. John McGucken and his film crew at one point visit a monastery, I think in Romania, that has this issue. When a monk dies, they exhume the oldest and place it in an ossuary, open, with the other exhumed monks. It's literally just a pile of bones.
Some of them are myrrh-streaming. Those are kept in a separate room in their own jars to collect the myrrh. Over time, the myrrh turns the skull a rich brown and eventually black.