What is the best insulation material for a lunchbox??? And please make sure it is so what Eco-friendly
Best insulation material is a perfect vacuumThe Thermos brand drink container is the best for liquidsFrankly, for other stuff, it works better to throw a hot pack or cold pack depending on what temp you need into any lunch boxI would use one of those soft lunch boxes like the link belowtypical food in a lunch box doesn't have enough mass to keep the temperature in the lunch box without added heat/cool.
If you have a magnet you could tell the steel ones but the metal recovered would be very little.
