To make a memory foam pillow fluffy again, it's important to keep it dust-free and exposed to sunlight from time to time. You can also fluff the pillow manually by kneading and pushing each section of the pillow or gradually pulling out clumps between your fingers. Additionally, placing the memory foam pillow in direct sunlight is another way of making it soft and fluffy. To extend its life, you can use a cover for the pillow for added protection from dirt and dust.