Milk bottles before the 1930s were a round shaped bottle. In the 1940s, a square
squat bottle become the more popular style.
Milk bottles since the 1930s have used pyroglaze or ACL (Applied Color Label)
to identify the bottles. Before the 1930s, names were embossed on milk bottles
using a slug plate. The name was debossed on the slug plate, then the plate was
inserted into the mold used to make the bottle - the result was the embossed name
on the bottle.
By the 1960s glass bottles were replaced with paper cartons.