Answer:
You heard me before, yet you hear me again, then I die. Until you call me again.
What can go through glass without breaking it?
Look into my face and I'm everybody. Scratch my back and I'm nobody.
Thousands lay up gold within this house, But no man made it. Spears past counting guard this house, But no man wards it.
It is weightless, you can see it. If you put it in a barrel it will make it lighter?
Keep doing me to avoid lens dryness