They can be taken out. To remove wrinkles from paper, you need an ironing board or a smooth, flat surface such as a countertop or sturdy, heat-safe table. You’ll also need an iron, a spray bottle filled with distilled water and some type of absorbent material. Hand towels, pillow cases or sheets work well for this project; you can also use thin pieces of cardboard such as poster board, although fabric usually works the best. You can use paper towels; but the textured surface might imprint the paper you are ironing, and inks and dyes can be transferred as well.

https://www.youtube.com/watch?v=dWzREJ7G3cE