UPVC cache

Contents look pretty much like what I had in my "survival kit" when out camping as a kid.

Regarding the kinder eggs - I've got a few items in a "pavlova egg" (twice the size and thicker than a kinder egg), plus have used film canisters for various things. Would need to be lucky to find them these days though.

One question -- how easy is it to find Condy's crystals these days? I remember buying them at the chemist years ago, but I think they're on the restricted list now due to being used in meth production.

That looks awesome, thankyou for sharing!

for small plastic eggs like that try Yowies - they're like kinder surprise but without the holes in them

I'll mention that this cache was either in a shed or a house. So the temperature could have varied from around freezing up to 40 degrees. Buried caches will usually experience smaller temperature variation so the contents may last longer.

First picture:

Puritabs all effervesced to nothing as usual. There was a faint chlorine smell but nowhere near the expected level. Don't count on these working after 20 years!

Aspirin also retained their effervescent feature though some took a little longer than others. Of note is they were sealed in foil not plastic as most are today. No idea if the active ingredient is still viable. Someone else might know the useful lifespan.

Hexamine solid fuel lit and burnt as normal, also appeared normal but didn't have a lot of smell.

Salt tablets (top right) are possibly discoloured. I think they were white on storing. Smelled OK and a nibble just tasted salty, not off.

Band-aids stuck well. Still wearing one now after a couple of hours. Note that these are the good plastic type made by J&J years ago. They DON'T come off until you take them off. I don't think these are available any more (GRRR).

The Condy's crystals created the usual purple solution. There was an expiry date of 1991 on the jar. This chemical is an oxidizer so it may have lost potency even if it doesn't appear to have done so. Unsure. I'll grind some with sugar to see if it burns in the next couple of days.
The metal lid of the jar didn't rust. But I doubt if glass jars with metal lids are available anymore so not really relevant.
Also I should have mentioned in the OP that KMnO4 and sugar mixed 9:1 and crushed together produces a powder that is very flammable. The addition of glycerin to this powder will produce spontaneous combustion. Fun to play around with!

Pencil and paper were fine. The first testing squiggle was faint to begin with and got darker as it progressed. After sharpening, the second squiggle is consistently dark. This suggests that pencils don't have an infinite lifespan but will dry out or degrade eventually. But this may take a century!

Stock cubes had some leakage of the ingredients out from the individual foil packaging. Unwrapping the cube was difficult as it was stuck on in places. No unusual smell was noticed and a nibble didn't taste any different than when packed. Originally they were meant to be crumbled into already boiling water as a soup substitute.
I added one to boiling water and let it boil for a couple of minutes. It stank and tasted disgusting. The others that I threw in the fire also gave off a hideous smell. Definitely not usable.

Of note is the plastic container (bottom right) which was sealed with masking tape. The tape was still sticky and the container sealed but it was very difficult to remove. It needed to be scraped off with a fingernail and tore frequently. Way too tedious for a SHTF situation. Masking tape was used originally because of concerns that the adhesive on PVC electrical tape might leak or spread contaminating the contents. Masking tape isn't suitable for long term storage. Use PVC or other tape for sealing instead.
Oddly the masking tape peeled off of the other sealed container in one piece. I did, however, use a lot of care to remove it.

Second picture:

One balloon was fine.
The other tore near the neck when I tried to inflate it.
Both were sticky, the sides didn't move freely against each other when slid between my fingers, but the blue one separated as it was inflated while the yellow one just tore.
This was expected. I stopped using balloons a long time ago because of this.

Of note is the ziploc bag which held the candle. The candle was place in the bottom and the bag sealed and then rolled up around it. The candle is in as new condition and lights and burns as expected but the plastic bag has wrinkled slightly where it was in contact with the candle. This wrinkling also carried though the plastic into the next layer. Something, either wax or an additive has affected the plastic. The bag was still airtight but be aware that candles aren't inert and may affect nearby items.
Also when I refill the cache I will cut the candle into smaller segments to make packing easier and so more flames are available if it is ever used.
Tip: for firelighting use a match to light a candle, then light the fire from the candle. This gives you plenty of time to light the fire and saves matches if the fire doesn't light first time.

Non-pictured:
Reflective emergency blanket was as new. As bushdoc says, exposure to heat will make them stick together. In my experience carrying one in your pocket for a month or two will do the same thing. They become difficult to unfold and the reflective silvering comes off.

The lightstick didn't work. This was expected. I have had them work up to 5 years old but this is very rare.

Both lots of matches lit as expected. Both from striking on the original matchbox and on a current day Redheads matchbox. This was expected. Matches stored in an airtight plastic bag will last for decades. These were Coghlan's Wind and Water Proof matches, made in Aus. and Greenlites waterproof matches in the cardboard matchbox, also made in Aus.
Forgot to mention that the matches had been repacked. As many matches as possible were packed into each matchbox (65 for the waterproof and 35 for the wind and waterproof) and the remaining space was stuffed with cotton wool. This provides tinder for firelighting as well as stopping the matches from rattling around and making noise.

I opened the personal survival kit too. Will add a post about the contents.

As you can imagine a buried cache here is not a good idea 8-9 months of the year.. Not with a frost line that can go 2+ meter deep...

We can get "vertical" ammo cans that are 82 cm tall. About the size of a 50 cal can and that tall.. This in roughly 1.5 cubic feet. You would be surprised what will fit in that amount of space.. It has been suggested to paint one to blend, fill and hang in a tree just high enough to keep it out of the snow. Be sure to grease the gasket seal with petroleum jelly to assure a tight seal and non stick to other surfaces.

You still may need snow shoes to get to it, but it won't be encased in frozen ground..

They are very good ideas. Thank you. I will be trying quite a few of them.

Special thanks for the sealed straw idea. This is excellent. It would also allow small quantities to be measured and stored to make it easier to mix them together in the appropriate ratios.
And for the tip on the CNOC water bags. I had no idea these existed. A water bladder that can be quickly filled and easily cleaned. Fantastic. (forum need a "thumbs up" smilie!)

I should have mentioned that this is an example of what I call a "get another 10 miles" cache. They aren't intended to keep you alive for long. Just long enough to get to a better equipped cache or location. If I actually need one then things are really bad! So they are just buried forever. Current ones contain only items that don't expire or degrade.

I checked the Condy's crystals/KMnO4 with the expiry date of 1991. Mixed it with sugar in a ratio of KMnO4:sugar of 9:1. Crushed it together with the side of the glass bottle. It lit easily with a match and burned well. Looks like this chemical will last for decades in storage.

That is a very good question!

I mixed some and split it into two piles.
Put a couple of drops of water on one pile until it was wet but not runny. This wouldn't light.
Left it to dry and held a lit match against it. It took a bit but it did burn. The pile had dried as a clump. If I had crushed it again it would have burned better.

The dry pile burned fine.

Vaseline impregnated cotton wool balls will for sure.  So does Wetfire but the stuff is expensive. 

www.bestglide.com/wetfire-tinder-cubes-ultimate-survival.html

What about the kero(?) based BBQ firelighters. They might burn when wet. Cheap to try and easily available.