Published documents reveal a mass rejection of copper/bronze for use as weapons and cooking utensils taking place around the 7bc or 8bc mark.
Hoards of copper/bronze utensils, tools, shields, arms etc from these dates have been found in rivers, buried in fields, in woods and some still remain undiscovered.
Why such a sudden and unambiguous rejection of such a source of livelihood?
Perhaps one solution to this conundrum is that this source of livelihood was intrinsically poisonous to them and they did not know that beforehand!
"It gets curiouser and curiouser"
(Alice in Wonderland Lewis Carroll)
I will copy this to my online archaeology post.