Lead stains can be got rid of by an application of peroxide of hydrogen, or even hydrochloric acid; but the greatest care will have to be exercised in handling the latter, or it will corrode the paper in a very short time, causing it to crack and break to pieces. If mixed with its own weight of water, and to three parts of this compound one part of red oxide of lead is added, its power for evil will be very materially diminished; but even under these circumstances it is dangerous to use. Each of these remedies has to be very carefully undertaken, as the fatty matters in the printer's ink are exceedingly liable to resolve, in which case the book will be spoiled. With care and attention I doubt not that almost any book can be very materially improved, if not made quite as good as new, by a combination of the processes described; and the best plan is to practise on some dirty and worthless specimen until the requisite degree of proficiency is attained. A "Literary Note" in the magazine entitled _Book Lore_ for July, 1887, observes as follows: "The renovation of books is, of course, a work of art in itself, and so clever are experts in the manipulation thereof, that many a dirty and decrepit volume has left their hands looking quite fresh and new. One of the most difficult processes has hitherto been to take dirt off the leaves without injuring the print. With this object bread crumbs were at one time used; but modern science has discovered three ways of effecting the same object in a much more satisfactory manner. Oxalic acid, citric acid, and tartaric acid, when in solution, will eliminate every trace of dirt without in any way acting on the printer's ink. Writing ink is not, however, proof against the attack of any one of the three, and this, too, being considered for the most part as 'dirt,' comes out with the rest. If the leaf is afterwards bleached with chloride of lime, the regenerating process is complete. The remedy for oil stains, it may be observed, is sulphuric ether. If the stains are extensive, it is best to roll up each leaf and insert it into a wide-mouthed bottle half full of ether, shaking it gently up and down for a minute or so. On its removal the oil marks will be found to have disappeared, and, as ether rapidly evaporates, a little cold water is all that is afterwards required. Mineral naphtha and benzoline each possess the property of dissolving oils fixed and volatile, tallow, lard, wax, and other substances of this class." Worm-holes, another source of disquietude to the collector, are caused by grubs, which are popularly supposed to be the larvae of beetles. They bore a circular hole through all the leaves, utterly destroying the appearance of any volume upon which they have fixed their attention.