By far the most common container recommended is the tobacco tin as recommended by Lofty Wiseman. You often read that the tin can be used to boil water - the average size of tobacco tins I've found is about 225ml (7.6 fl oz). Considering fires are rarely perfectly level and water bubbles as it boils there is no way you could get even that much water into the tin.
Now, these tins are good for fitting in pockets - particularly jackets and combat type trousers - and are robust, cheap and readily available. The trouble for me with this container is that, according to the rule of 3s and Cody Lundin's excellent book water is actually a pretty important factor.
The Rule of 3s
As a quick reminder to all of us here is the rule of 3s;
3 minutes without air
3 hours without shelter
3 days without water
3 weeks without food
3 months without hope/human contact
Remember that this is a very general guideline, it may be different depending on weather, helath, activity etc. With the "average" survival scenario running up to 72 hours then we can see that some water, especially warm water, would be a useful thing. A solid pot can also be used as a shovel in snow or when building a debris shelter.
Boiling water for as little as 1 minute (at sea level) will kill anything that can be killed through boiling.
Last Things First
To this end I tend to think of kits as being built backwards from their container as this is what defines what can be carried. You can see a fine example survival kit following this logic using a Swiss Army canteen over at Woods Monkey. I have previously tried using a tin mug to make a sort of brew kit using a tin mug as a container and a plastic bottle which originally contained about 50 bits of chewing gum.
The Old Tin Mug
The container is a standard sized steel mug, probably not a lot bigger than 250ml capacity but due to its shape a lot better for boiling water in. Lower surface area means less chance of water jumping out when it boils and the handle makes it an awful lot easier to pick up afterwards than a tin. The kit simply consists of a wax stove, mug, plastic bottle, tea bags, matches and a pack of soup to stop it all rattling about. I've got some old information, complete with rather poor pictures here.
There has been a fair bit written on various blogs of the fads and fashions in bushcraft as a hobby. I've never been to a big meet so I've yet to see a horde of Swandri clad Gransfors axe wielding clones - the Zebra billy can is another one of those items on the bushcrafter's must-have list. From what I've read it is an excellent pot and trying to find a real pot in a camping store at a sensible price is like looking for a needle in a haystack. I am very interested in getting hold of the biggest size, the 16cm pot, which has a 100 fl OZ / 3 litre capacity. Why so big? You can always put less in a big pot but you can't put more in big pot. This size may be a little on the large size for a survival kit - if it's too big then the likelihood is it won't be with you when you need it! Ben's Backwoods stocks all different sizes down to the 10cm pot.
Civil War Vintage
Just because something's old doesn't mean it's bad; and that's cetainly true of the American civil war vintage mucket. As the name suggests it's a blending of "mug" and "bucket" into the portmanteau "mucket". In Britain I suggest going to Warhorse Sutler (bottom of page) and checking out the stainless steel version - not authentic but not rusty like a tin one. These little pots usually hold about 750ml and contain and integral lid (with lifting knob or hook) and bail and are excellent little bits of kit. I used them often back in my reenacting days and seriously recommend them as a good pot and container for a survival kit.
Re-use and Recycle
An old tin can may not be glamourous but it gets the job done. I find that tinned fruit cans are a very usable size - all you need is some pliers, an old coat hanger and a sharp point. You simply punch holes through the top for the bail and then bend the wire into place. With judicious slection you could find a smaller can to go as a lid/frying pan and then you can seal it all up to make a complete container and cook kit for peanuts. Some of the old timers went into this in a bigger way and Wildwood Wisdom has a couple of pages devoted to tin can outing kits.
The Industrial Approach
What about if you're making a long term kit, bug out bag or family kit? In that case I'd have to go for a proper steel bucket. Don't get a dodgy looking galvanized one from a garden centre but a proper, nigh-on-indestructible, one from a catering supplier. They have lids handles and come in up to 15 litre (nearly 16 quarts) capacity. Think about it - if you need to clean water for cooking, cleaning and washing - for example after a flood when sewage is flooded out of drains and tanks and up onto street level - what type of container do you need? I've even seen recommendations on preparedness websites suggesting a bucket, filled with useful materials, food etc. makes a great gift for getting people into the idea of preparing and making contingency plans. For serious base camps, the heavy duty steel and bail is a good combination and even makes Jack Mountain Bushcraft's kit list.
A Master's Opinion
I couldn't end here without mentioning some of the things that Mors Kochanski, one of modern bushcraft's greatest practioners, has written on the subject of pots in survival kits. In an article in issue 5 of the BCUK magazine (no longer in print) he wrote that a good pot needed a lid that could be tied down, to be made from solid guage steel, to have rounded corners for ease of cleaning and a bail. He also stated to buy a pot twice the size you expected to need. In his booklet, "The 2 Kilogram Survival Kit Field Manual" he mentions using a 3 or 4 litre oil can, suitable cleaned. In his booklet "The Tools of Survival and Survival Training" he mentions the need for a pot of 7 cup (1.6 litre) capacity with a tight fitting lid with a ring, not knob, and a strong handle.
I hope you have seen that there are lots of good container/cups/pots to build a survival kit around and that the ability to purify water is an essential part of any kit.
I hope to get hold of some of the above mentioned items for review over the coming months and also put together a tin-can cook kit for budget bushcrafters. If you know of any good reviews of alternatives, or the items mentioned above, please drop me a line.
Photos on strange backgrounds are my own, others come from the websites of suppliers linked in the article. If you wish them removed then there is a link at the top with my e-mail.