Yes, you can. You can transfer the leftover hummus to an airtight container and add a thin layer of olive oil over the top. The oil helps preserve the color and flavor of the hummus. Store the hummus inside your freezer for up to 4 months. To use it again, all you have to do is thaw it at room temperature or inside the fridge. Once it has been completely defrosted, give it a good stir with the layer of oil and serve immediately.