Green two vented metal bell box

[Jack b]

Hello anyone know or have an idea as to what's inside this old bell box?

[norman]

Old wasps nest would be my guess. 

[al-yeti]

Rust caused by boiler steam vent

[Jack b]

4 hours ago, al-yeti said:

Rust caused by boiler steam vent

Your not wrong. There is another one of the same bell box in my area that hasn't rusted so it makes sense that the boiler steam vent would be the  cause