'Just Walnut' in other words walnut crystals. These can be sprinkled directly onto paper and activated with water for some intense brown aged effects. You can also make up solutions to different strengths in a water-misting bottle and have it to hand to spray, drip or blob onto surfaces for that instant vintage, sepia effect.
To dispense, simply poke a hole in the cap and sprinkle in the concentration of your preference. You can use a push pin and then keep the push pin in the cap.