First, read the English article below.

You can cook the prawns in their shells as well, removing them later, and this often helps them retain moisture as they cook, But if the prawns are part of a larger dish (like a soup) you don't want to search for scales with your spoon. Luckily, cleaning prawns is easy before cooking.  If you are grilling or pan frying your prawns, you should leave at least the shells on. You can leave the heads on the prawns, as they will lead to a stronger flavor, but many people remove them to make eating easier. They should come off with ease. Grab around the eyes and firmly twist to pull the head off. You can discard these, or save them to make seafood stock. Simply use your hand to pinch off the small dangling legs and pull them away. Starting at the larger end, work your thumb under the shell and slide it down to the tail, pulling off the shell as you go. It may come off in pieces. You can either leave the tail on, usually as a "handle" when eating by hand, or remove and discard it if you're cooking the prawns into another dish. You're looking for the long black vein that runs through the entire prawn. It is easiest to see near the tail, where there is a small valley in the prawn. Pull the end of the vein up with the tip of the knife then grab it with your fingers to pull it off. This is not strictly necessary, but the vein has a bitter taste that is best removed now. You can still remove the vein while leaving the shell on. To do so, clip the shell with scissors and pull the vein out, closing the shell back up. You can also pull the entire vein out in one piece if you break the head off and locate it. Moisture on the outside of the prawn will make the cook unevenly. Give them a quick rinse with cold water and then dry them off. If you don't plan on cooking them yet, keep the prawns on ice or in the refrigerator. 

Now, please write a short abstract for it in Vietnamese. Abstract:
Bóc vỏ và đầu tôm để dễ ăn hơn sau khi chế biến. Bỏ đầu tôm bằng cách kéo và xoay. Bóc chân tôm. Bóc vỏ tôm bằng ngón cái. Dùng dao nhỏ rạch một đường dọc theo lưng tôm. Bóc sợi chỉ đen ra khỏi tôm. Rửa tôm dưới vòi nước và thấm khô bằng khăn giấy.