WHY MANY OLD BOTTLES
Bottle collectors will tell you
most older bottles they find
(especially those found outside)
Commercial glass bottles and jars
from the 18th, 19th and early 20th century
contain large amounts of lead.
This lead glass, originally colorless,
gradually turns blue when exposed to sunlight.
You can place a 19th century clear bottle
in the sunshine over the summer
and it will start turning blue by year's end.
It's quite common to find older glass canning jars
in beautiful shades of blue and green.
(And they're still perfectly safe for storing food.)