Clean water - it could be boiled with metal tanks and steel jerrycans.
Errrm… This is… already in the game…
I think perhaps they meant that metal tanks and steel jerrycans could be used to make clean water as well as the current pots/stone pots.
Edit: For the record, I support this idea.
If thats the case, the game should allow the player to massively craft water. 25 litres per craft or so (like 50 plastic bottles)
Just manually craft is once and recraft with the - sign.
In a keypress log this would be something like.
&>>>>[Enter] (container)
- (container) - (container)- (container) - (container) - (container)- (container) - (container) - (container)