I used to use a small Altoids can for my PSK. In a short while, I questioned myself, "Why?" I eventually concluded:
1) I could comfortably carry a larger PSK than a small Altoids tin in my pocket all the time;
2) more room would give me the ability to carry slightly larger items, slightly more items, and slightly more supplies of items, each of which could greatly increase my chance for survival, should I actually ever need to rely on my kit;
3) the mini Altoids tin, itself, was pretty much dead weight, whilst other possible PSK containers could serve useful functions.
So, I ditched the mini Altoids tin. I made my own container, a fairly small (6"x12"), lightweight (2/3 of an ounce), roll-top waterproof bag. I carry my kit in that, with the top rolled down and sealed. I can fit everything I need to into it, easily (takes up about 2"x3"x6" filled with my PSK, then rolled down and sealed, and weighs about a pound). It keeps everything inside waterproof, and it doubles as a water bag, able to hold about a gallon, when sealed watertight.