It is important to use freshly plucked leaves. Older leaves tend to dry up and turn crumbly and will break when you shape them into cones. If you plan to source them from somewhere and will make this dish after a gap of a few days ensure that you wrap them up very well. To do this, take a a clean kitchen towel and soak it completely in water. Then wring/squeeze it to remove all the water. It should be only damp and not dripping with water. Spread it out, place the leaves inside and wrap them well. Place this cloth packet inside a large ziplock/polythene bag in the crisper drawer (vegetable compartment) of your fridge. The leaves stay well for upto 7 days.