Homebrew PCBs

WalMart sells dilute Hydrogen Peroxide (3%) in brown, recyclable HDPE
bottles.  So, if you replace
it every year or two, I would guess HDPE is a great storage for H2O2.

If I remember right back in high school (think late 1960's, before
HDPE was popular) we used
glass bottles for almost everything, and polyethylene bottles for
basically the same stuff, just
as transient containers (think students handling this stuff in high
school - scary thought)

We only had one injury I heard about that is more than minimal.  One
of the lab techs was in the
store room when the water evaporated down low enough so metallic
phosphorus was exposed to
air.  He was mainly surprised when it exploded (chemically, not an
explosion, just a fast burn
as the phosphorus was exposed to more oxygen in the air) and stuff
came off the shelves in the
store room and hit him. ... minimal injury really, but enough to be
reported.  The metal tin the
phosphorus was stored in was not closed sufficiently (it was like a
paint can) so eventually a
good covering of water evaporated exposing the phosphorus.

sorry about the rambling...

In short, HDPE or PE should be good for storage, just don't consider
it permanent storage.