For many people, blue jeans are a wardrobe staple. Their color comes from a blue pigment called indigo. Indigo is not soluble, or able to dissolve in water, so manufacturers must mix it with toxic chemicals to dye denim. That’s why scientists from the University of Georgia have been experimenting with greener ways to make jeans blue.

The researchers mixed indigo with nanocellulose, a substance made from wood pulp, to create a gel that can be applied to fabric. The nanocellulose helps the dye stick to the cloth, creating a more vibrant color than typical dyeing methods. And since it doesn’t require harsh chemicals, it’s better for the environment.