Separate the coffee filters into groups based on what color you want to dye them.

Gather your bowls (one for each color dye) and put between 10 and 20 drops of food coloring in each bowl. Use glass bowls if you have them to avoid staining.

Add 2 cups of water to each bowl and stir until the food coloring is well-mixed with the water.

Put the filters in the bowls one at a time. You can add multiple filters to each color bowl, but make sure all filters are submerged. We find that 10 filters per bowl is about the limit.

Let the filters soak for 30 minutes. The longer you let the filters soak, the darker the color will be.

While the filters are soaking, line a baking sheet with paper towels.

Remove the filters from the bowls and place them flat on the baking pan on top of the paper towel. When you run out of space, put down another layer of paper towels and start placing filters on top. Keep placing filters in layers separated by paper towels until you have all the filters on the baking pan.

Important! Make sure the filters are flat. If any filters are wrinkled, they won't dry, and the color will run.

Once you have all the filters on the baking pan between paper towel layers, pat the filters to squeeze out the water. Take your time and be thorough. The goal is to remove as much water as possible during this step.

Now you have to dry the filters. You can either separate the filter layers from step 7 and let them dry, or you can place the filters on a parchment-lined baking sheet and put them in the oven. If you have time, we recommend letting the filters dry overnight. If you are pressed for time, preheat the oven to 250°F and bake the filters for 5 to 10 minutes. Watch the filters carefully while they're in the oven, so they don't burn.