Cotton, so they absorb like magic. They work like store-bought cleaning pads, but these are re-usable and go straight into the wash. When I make mine, I make them in sets of 7 or 14.
CH 4. slipstitch onto the 1st ch st.
CH 2. 12dc into the hole. slst.
CH 2. 2 dc in each dc. slst.