+1 for the techni ice here as well!
and the block ice.
I haven’t found any around here but in Broken Hill you can go to the ‘ice factory’ if that’s what it’s called and buy ice in nice big blocks which last almost forever!
Instead I too freeze containers, the bigger the better, but I freeze it for weeks (some people say it lasts longer and what would I know?)
The techniice sheets are good for those lttle cooler bags the missus should take to get he shopping but not much else really.
Someone once told me salt water is better frozen but I couldn’t tell the difference in performance. It doesn’t taste real good when thawed either!