"The fire had got at them and damaged them badly."

Bronze Axe-Head From Crete
GNU Free Documentation LicenseBronze Axe-Head From Crete - Credit: Chris 73/Wikimedia Commons
When bronze oxidises it does not become brittle like rusted iron. However the acids, sulphur and other damaging components of smoke can cause a destructive corrosion called ‘bronze disease.’ This would destroy bronze weapons left too long by the fire.