About a month ago, I saw this tutorial on kitchn.com and tried it.
Emily takes her lunch to school and needed cold packs but usually they are too heavy or bulky.
This looked perfect and after a month of using it, I love it!
Here's the tutorial and above is what we used in ours. I did not use food coloring because I was worried that if it did leak the food coloring might stain. So I just used dish soap that was pleasing colors to begin with:) And we added glitter although that was pointless (might be because of the color glitter we used; you can't really see it when frozen or thawed).
The girls added thin plastic toys.
And after putting them in the freezer, they look like below. I purposely froze the green one folded to see how it came out.
It was perfect to cradle her milks but I don't do that anymore. I just freeze it flat and line her lunch box with it. Then pile everything in.
I pack her lunch using one dish soap ice pack and two palm sized hard plastic ice packs She takes yogurt, milk and cheese so we need it to be cold all day. I pack it at 7:15am and when she gets home at 3:15 it's still cold but not frozen (the hard plastic ones from Target come back home warm). . The blue one did leak the 1st time she used it but not all over the place so I double bagged the green one and it help up till yesterday (about a month of daily usage). So if you're looking for an easy lunch box ice pack, this is it!
I was a little irritated when reading the comments from the tutorial on the actual site. It just seemed like a lot of those people had nothing better to do then slap down other peoples ideas.
The pros to this are that it's super light weight, stays cold for a loooong time, is still pliable when frozen and if it does leak like it did with mine, it takes time for it too ooze out of a small hole where if it was water the smallest hole will leak all that water out in minutes and be all over the place. There was no mess outside of her lunch box as there would be with water. So if you're looking for an easy, cheap ice pack alternative this is it! And I'm even thinking about making small ones for the airplane (under 3oz).