This section is from the book "The Gardener's Monthly And Horticulturist V23", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
In skeletonizing leaves it is important to select leaves that are quite perfect, for if any of the fibres have been eaten away by insects when the leaves were on the tree, the skeletons will be unfit for grouping. The leaves should also be full grown and firm in texture, and for the leaves of the majority of plants June and July are the two months for taking them. Gather with the whole of the leafstalk, and immerse in a vessel of clear soft water, and allow them to remain in this until the soft part of the leaves divides readily from the fibrous matter. As some leaves require a longer time than others, they should be examined occasionally, and those sufficiently decomposed have the soft part removed. To do this nicely, time and patience are alike necessary; for if there is any undue haste they will be either torn or not thoroughly cleaned. The best way perhaps of separating the two parts is carefully rubbing the leaf between the thumb and finger in a vessel of clean water. When the skeleton is cleared of the soft matter wash it in clean water, and then lay it perfectly flat on a piece of paper rather porous in texture.
In a general way, it is best to take each leaf out of the water with the piece of paper on which it is to remain until dry, as there is then not so much risk of its being injured in any way. When partly dry, they should be bleached in a weak solution of sulphuric acid. As the leaves differ so much in the strength of their fibres, and in the time required for bleaching them, no precise rules can be laid down for the quantity of water to be added to the acid, or the length of time the skeletons are to be immersed in it. A little practice and observation will enable the operator to arrive at correct conclusions upon these points. If the solution is too strong, the fibres will become so brittle as to snap on being handled in the most careful manner. - Gardener's Magazine.