You will need:
Kalamata olives, salt, vinegar, olive oil
Take 30kg of Kalamata olives, rinse them well and make incisions in them with a razor blade or with the purpose-made tool, rinse them again, put them in a barrel and cover them with water.
Leave them there for 10 days, changing the water every day. On the last day, add 3 kg of coarse salt to the water. (There is enough salt if you put an egg in the water and it floats.) Leave the olives there for 5 days or for as long as you want to preserve them.
If you wish to put them in jars, take them out of the salt water, put them in a big basin, add vinegar (about 3 bottles) and leave them there for a day. Remove them, place them in jars and cover them with olive oil.