Identify maker of milk bottle

[Lloyd Levine]

I picked up 6 milk bottles recently, but aside from the year it was made, there is no identification on what dairy these came from. Does anyone know how to identify these bottles based on the code stamped on the bottom ?

[Michael]

When the particular dairy is not displayed on the bottle directly, it may mean the bottle is simply a generic milk bottle not assigned to a specific dairy.  Therefore, mass-produced and cheaper for the dairy to purchase.  The code M 3238-S may simply be the bottle code not a dairy code.

When the milk bottles were made with the particular dairy emblazened on them, it was usually obvious enough which dairy it was that a particular code would not be necessary.