What happened to the eggshells of fighter planes after firing in World War II?

From World War II to the present, the shells of fighter guns (guns) are thrown out of the body immediately after firing.

Mainly for these reasons:

1, it's not easy to collect, and the space of the plane is limited, so it's difficult to leave a special place for loading shells.

2, the value is not great. Although the shell casing has recycling value, it is uneconomical compared with the load and space of the aircraft.

3. Security and reliability issues. If there is room for loading the shells, the shells can't be stacked neatly, especially when the plane often moves irregularly at high speed, which will make the shells run around. If the shell throwing window is blocked, it will cause the cannon to jam and even cause damage to the aircraft.

At present, although the external gun of Zhi -9 can be equipped with a shell collector, it is rarely seen.

You can consult and hope to adopt it.