Why would cleaned milk jugs be any more likely to contaminate any more than a cleaned jug of other vintage?

Milk jugs are designed to degrade when exposed to the elements though, so they are not real good for longer term storage.

ILBob, check the FEMA preparedness manual I linked to in this post from last month regarding why.

I suppose it is possible. I am more worried that the plastic will deteriorate over time as it is designed to do.

Use 2 liter pop bottles for the freezer. Contrary to what might make sense... fill them FULL, then freeze. (Yes, I know that water expands ~9% when it freezes) So far <knock on wood) I have not had any bottles split and none have even fazed the cap - frankly, most don't even noticeably bulge. These bottles are relatively heavy gauge PET and are designed for a modest bit of pressure from the carbonation. This is far superior to milk jugs and the water is potable when the bottle thaws.

We don't drink much pop, but friends save the bottles for us. I do a light rinse with tap water, leave the caps off, and then when I have enough to make it worth my while, I "process" a batch.

Sorta like washing dishes - wash, rinse, sanitize, air dry. Sink with hot water + Dawn, sink with clear water (refreshed as required), one bottle half full of water + plain bleach. As a bottle is washed and rinsed, the sanitizer bottle contents are transferred; shake it up to coat inside of bottle with sanitizer (clean cap kept on counter for that) and set it down. Now-empty sanitizer bottle slung out vigorously and leaned up to air dry. Wash next bottle, etc. I use a pretty hefty mix of bleach-to-water - no harm. Re-rinse with tap water if it bothers you, but... there's no need.

Last are caps and sometimes a dish scrub brush helps in the threads if you were not paying attention when you initially rinsed the bottles. Set out a small plastic container (e.g. margarine tub) and as the caps come out of the rinse water, drop them in. Wait one minute after the last cap is set in, then remove all and set aside to dry. Go slosh the "spent" sanitizer in/around your shower...

In theory the "pressurized" frozen water will have a lowered phase change temperature, but at the pressures we're talking - there's no change, despite internet myth. It still freezes at or around 32 deg F.

These don't freeze frothy - they're like lethal weapons when frozen <grin>. Think bowling pins.

Seriously, ditch milk jugs - nasty - use plastic PET pop bottles instead.

I get my canteens at the supermaket. They come prefilled with tasty fluids of various colors and a lot pseudo-scientific mumbo jumbo about electrolyte replacement. I drink the colored fluid as needed and refill with whatever potable water is handy ( I want all the electrolytes). They work quite well - cheap, light, and effective.

Ayers, it is good to hear from you again....

I never "left"... OK, maybe I got distracted for a bit. Grandkids started popping up... I'd say I'm too young for that, but sadly, not true... anyway, it's GREAT to see so many familiar folks still active here!

+1 on the beverages. I'm partial to those 24 oz bottles for tons of uses - inc. water bottles. Work great for breaking down big bags of rice, pinto beans, etc. as well.