Following on from Alasdair,
there is of course the issue of bottle recycling. I published a short article on the conversion of a beer bottle to a jam jar by cutting the neck off and blunting the resultant edge by retouching it. If the bottle/jam jar had been broken and then dug up archaeologists might have figured out - beer bottle and retouching on glass - a contact site!
Every so often there is a story about someone drinking some black liquid from a Coke bottle and being poisoned - the liquid looking like coke. Ironically as we alls should know the unique coke bottle shape was designed to signify that its contents was the real thing rather than some other manufactures beverage.
I am not sure how archaeologists can deal with bottle recycling but it certainly has the potential to undermine interpretations based purely on purported bottle function.
Iain Stuart
[log in to unmask]