Transfer dried maiz(corn) to a large bowl. Cover with water 2 liters of water. Stir and let sit for a few minutes. With a slotted spoon or your hands, remove all the pieces that float to the top and discard those. Let sit for 5 minutes.
In a large pot at medium heat, pour in three liters of water. Mix in five tablespoons of cal. Stir well to combine. It should taste sour. If it doesn't, mix in a little more cal(lime).
Drain the water from the maiz in the bowl, then transfer to the pot on the stove with the cal. Stir gently. Bring up to a boil. This may take 25-30 minutes. Stir now and then.
Once it comes up to a boil, reduce the heat slightly. The maiz will turn a yellow color and it will begin to float to the top. Some of the husks(skins) will start to fall away. Continue cooking at a light simmer for another 30 minutes.
Remove from heat and let sit for 1 hour or overnight.
When ready, drain the maiz into a colander in the sink. Under room temperature running water, use your hands to vigorously wash the maiz to remove any remaining skins. Once it looks clean, you can leave it as is, or you can remove the tips. Using your fingers or the metal spoon, cut tips away from all the maiz! I know! A labor of love for sure!
After that step, you will need a break for sure, lol! At this point you want to cover the maiz with 2 liters of water and mix in 1 tablespoon of baking soda. Stir well and let sit for one hour. This process will whiten the maiz a little more. It is optional.
Drain maiz after one hour and rinse well under cool water. At this point you can package maiz in freezer bags and store frozen until you are ready to use it for pozole or menudo.