What's wrong with glass canning jars?  They are strong---made for boiling and
freezing and meant to be re-used many times.  They are quite cheap, and in the
US they can be bought at your local supermarket (especially in late summer, of
course).  They come in many sizes down to about 4 ounces, or maybe it's 6.

When I was a hospital nurse we were told---by administration? by the formula
reps?---that the water and formula bottles provided by the companies were
meant to be used once and thrown away, not re-used, and thus were of a weaker
type of glass that would chip more easily.  I don't know whether this was
true.  The formula reps certainly had no incentive to make milk expression and
storage any easier for us or our moms.

When I worked night shift in the nursery I sometimes finished my 8-hour shift
with a whole bucket of empties to bring back for the hometown glass recycling
program.  Just another bit of info about the sorry state of infant feeding at
my former workplace.  Single-serving packaging is surely the most wasteful way
to formula-feed!

That last paragraph is a tiny rant to start 1999 off right.

Peace and justice to all of us for 1999.

Chris