Universal absorbents are absorbent pads, socks, and pillows that can absorb a variety of liquids. They can work with oil-based liquids, water-based liquids, coolants, solvents, and the like.
Conversely, oil-only absorbents are made to absorb only oil-based liquids. They are also often made of hydrophobic materials, which means that they’re not compatible with water-based liquids.