Containers for food was an early concept for pressed glass.  Among the first were jelly glasses (see above early Honeycomb pattern). About 1875, glass companies began making inexpensive covered containers and other forms of glass which they & their distributors called "Packer's Goods".   These came with metal or cardboard or even matching glass lids.   The description would indicate that the company buying the glass vessel could fill it with anything of their choosing.  Thus the consumer obtained the glass by purchasing the product which it contained.  This is corroborated in Dr. Herrick's Greentown book refers to the Dolphin and states: "This was a mustard container, filled and handled by grocers."        
       The containers included glass candy containers, milk glass cov'd novelties, children's' & various other small mugs and EAPG patterned covered jars (which we now call 'mustard pots') all of which could be used after the contents were consumed. A few of these are shown in the photo below.  On some you can see the top edge which once was fitted with a metal lid.
A catalog reprint showing a few of the types of Packers' Goods used.
These would be drawings and not necessarily true to the vessels it advertised.
This is a drawing from a Westmoreland catalog showing  a handled egg cup which may have been the same vessel in the catalog reprint on the left.
      Above is one such popular child's mug which had the word "DARLING" pressed into the base of the mug bowl. The rim where the temporary disposable metal lid fit can be seen on this piece.     It is 3 1/4" tall.  LATE PANELLED GRAPE, pattern line #650 of the D. C. Jenkins Glass Co. of Kokomo and Arcadia, IN. 
We have 2 @ $35 each.
     The Packers Goods condiment/mugs above are:
Left: MULTIPLE SCROLLS by Canton Glass Co. c. 1893 $22;
DRUM with gold & an eagle by Westmoreland Specialty             Co. $23
Right: CHERRY WITH THUMBPRINT mug by Kokomo Jenkins           #475 c 1904 "Sweetheart" on the side; top is rough.  $25.
Many other "Packers' Goods" can be found
among our Toy & Drinkware WebStores.