Application Cone Making: This page details how one can make their own sealed plastic cones for henna application and temporary storage from ordinary plastic freezer bags. These cones are similar to so-called "carrot bags" (except they have two seams instead of one). Some, including myself, find this type of cone easier than rolling a cone, as problems due to leakage and getting a properly-sized opening are avoided.
Metal Tips for Plastic Cones: This page describes how to easily obtain precise .5mm and/or .7mm lines from your carrot bag style cone by using the tips from common mechanical pencils. This method eliminates guesswork in trimming the tip of such a cone, eliminates line distortion due to the seam(s) of the cone and stretching of the opening during usage, and provides for easier clog removal.