Silver Falls: 3 Down Stars Answers for 3DS

Where is lead box for last sphere in steel mill?

I found a lead box for the sphere in the silo by the steel mill, but that was used up for the sphere at Arnalts house. After using the lead box to retrieve the sphere at Arnalts house, I can't retrieve the sphere in the upstairs office of the steel mill because I no longer have the lead box. Is there another lead box somewhere? Or is this some kind of glitch?