To the saucepan, add 4 cups of water over high heat.
To the water, add your natural ingredient (beets, yellow onion peel, frozen blueberries, or purple cabbage) and bring the water to a boil.
Turn the heat down to low and simmer for 30 minutes, or until the dye has reached the desired color you’re looking for (you want it to be a couple shades darker than the color you want your eggs). The longer you leave it to simmer, the richer the color.
Once your dye has reached the desired depth of color, remove from the heat and let cool (for about 20 minutes). Then pour the cooled dye over the fine-mesh strainer into the mason jars.
Stir in 2 TBSP of vinegar into the strained dye.
Repeat steps 1-4 for each of the natural dye ingredients.
Gently place your hard-boiled eggs into each mason jar (about 2 per jar).
Transfer your eggs in the dye to the fridge and let them chill until your desired color is reached (at least 30 minutes, up to 24 hours for the richest color result).
Remove your eggs from the natural dye to a paper towel lined dish and dry them off.
Store your dyed eggs in the fridge for up to 2 weeks.