1, the rice balls are cooled and sealed with fresh-keeping bags, and the bag mouth must be sealed tightly.

2. Find a foam box the size of a lunch box, decorate the crushed ice with a fresh-keeping bag, wrap the rice balls in the crushed ice and put them in the foam box;

3. Just seal the foam box with sealant tape.

Crushed ice doesn't melt easily in a foam box, and the way to do it in a day is by air.

Crushed ice: put some water in the insurance bag and put it in the freezer for one night. Just take it out and break it with the back of the knife. If you want more crushed ice, freeze more.