First, read the English article below.

Lye can cause burns. Wear chemical-resistant gloves and safety glasses whenever you're working with lye, and don't use an olive vat made of plastic or anything made out of metal (even lids, since the lye dissolves metal).  Do not use the lye curing method if children might come anywhere near the olives or the solution. Complete the process in a well-ventilated room. Open the windows and turn on a fan to increase the airflow. This method works best for large olives, such as Seville olives. It may be used for either green or ripe olives. Pick out the damaged or bruised olives and sort the olives by size, if desired. Again, do not use a metal container; a large glass or ceramic. container is best. Pour one gallon of water into a lye-resistant container. To the water, add 2 ounces of lye. The solution will immediately heat up. Cool it to 65 to 70 °F (18 to 21 °C) before you add it to the olives.  Always add lye to water; never add water to lye. It will cause an explosive reaction. Use exact measurements. Using too much lye will be detrimental to the olives; too little and they won't cure properly. Cover the olives completely with the lye solution. Use a plate to weigh the olives down so they don't get exposed to air, which would cause them to darken in color. Cover the container with cheesecloth. For the first eight hours, just stir the mixture and recover it when you're finished. After eight hours, start checking the olives to see whether the lye has penetrated to the pits. While wearing chemical-resistant gloves, pick a few of the largest olives. If they are easy to cut to the pit, with soft, yellowish green flesh all the way through, the olives are ready. If the flesh is still pale at the center, submerge them and try again in a few hours. Make sure you never handle the olives with your bare hands. If you don't have chemical-resistant gloves, use a spoon to remove the olives and run them under cold water for several minutes before checking lye penetration. If the olives are very green, the lye may not... 

Now, please write a short abstract for it in Vietnamese. Abstract:
Thận trọng khi sử dụng dung dịch kiềm vì có thể gây bỏng. Rửa sạch ô liu. Cho ô liu vào thùng chứa kháng kiềm. Làm dung dịch kiềm. Đổ dung dịch kiềm vào thùng ô liu sao cho ngập hết quả. Đảo đều hỗn hợp 2 tiếng một lần cho đến khi dung dịch kiềm ngấm vào trong hạt. Thay dung dịch kiềm nếu cần thiết. Ngâm ô liu trong nước 2 ngày. Thử ăn ô liu vào ngày thứ tư. Muối ô liu trong nước muối nhạt.