A new consideration for the PSK H2O Container, the Aqua-Pouch. Note, I have not personnally tried to roll this up and squeeze it into an altoids tin.

There also is a kit which has a strainer for filtering dirt/debris.


http://www.bepreparedtosurvive.com/The%20Aqua-Pouch%20Plus%20Water%20Purification%20Kit.htm