After all I've been reading about chipboard, I came to the conclusion that I have plenty of it in my own kitchen. I started recycling cereal boxes, and any other kind of box in cabinets. Once a package is empty, it's ready to be used. I'll cut the shape or font I need for a LO, sometimes I'll use gesso (available in an Artist's Supply store or maybe Wal-Mart's, I haven't looked there yet), it will conceal any writing on the package and will use less paint in the long run, it basically works as a primer and hardens as it dries. Then it's ready for painting and/or decorating or layering paper over it.
By using gesso, you're also able to give a piece texture by dabbing with a sponge. When you paint it, use acrylic paints since I've read they are acid free.