Take the loose petiole (blade) between your fingers and pull gently. If the petiole does not come off easily, leave it. Palm flowers and fruits take energy and nutrients away from the tree, attract pests, and create hazards for people walking below.  Cut fruit and fruit stalks from the fronds or trunk and remove flower growth by hand. Fruit stalks and flowers should be removed as soon as they are visible. Place fronds in a trash bin made for organic waste. Palm tree fronds tend to have sharp needle-like protrusions that can prick those who handle the waste.  Continue to wear gardening gloves as you clean up debris. Pick up any fallen fruit, flowers or seeds. Pests that can harm the tree are attracted to dropped seeds and fruit. Fallen fruit can also stain concrete and produce unpleasant odors, and the seeds can germinate in undesirable places. Consult your local waste disposal service department to find out how and where to dispose of palm debris. Palm trees do best when left alone. Green fronds produce all of a palm tree's food. Keeping them around is integral to maintaining the health and strength of your tree. For that reason, you should never take off more leaves in one year than the tree can produce in that time.

TL;DR in Vietnamese:
Kéo các cuống lá lỏng lẻo khỏi lá cọ. Cắt tỉa hoa và quả trên cây nếu cây cọ của bạn thuộc giống cọ có hoa. Vứt bỏ các lá cọ, cuống lá và quả cọ đúng cách. Chờ thêm một năm (hoặc lâu hơn) trước khi cắt tỉa cây cọ lần nữa.