In the case of very stubborn specimens with this defect, they may be steeped in the peroxide and allowed to soak, but should not be left longer than is necessary to restore the original fresh colour. A crease in an unused stamp may, if it has not cracked the paper, be removed by following the crease on the back of the stamp with a fine camel's-hair brush dipped in water. The slight soaking swells the gum and enables one to gently press the paper into its normal position. Pressure in the case of a big crease is best applied by ironing, the stamp being protected between glazed cards. Where the gum is untidy on the back of an unused stamp it will sometimes be useful to lay it, after cleaning, upon the surface of smooth glass or the glazing-sheets used for glossy prints by photographers, which will preserve what remains of the original gum, and impart a gloss which compensates for a partial loss of gum. To preserve the tidy appearance of a collection in a printed album one must sacrifice those portions of the margins adjoining stamps from the outer edges of the printed sheets. In most cases it serves no purpose to retain them, and they interfere with the symmetry of the pages. The collector, too, must use his judgment as to the desirability of trimming away unnecessary ragged protrusions of the perforation. For all cleaning purposes benzine is an excellent medium, as its rapid evaporation is a convenience, and it does not injure the stamp. Most used stamps may be soaked in benzine and be much improved by the bath; but where the colours of the stamp are such that immersion in liquid is unsafe, treatment may be applied to the edges or to the back as required by means of the camel's-hair brush. The whole purpose of this care with individual stamps is to preserve the specimens and to impart a composite beauty of condition to the whole, without which no collection can be pleasing to its owner or to any one else. Every unused stamp should be spotless so far as extraneous blemishes are concerned; the colour should be fresh as when it came from the printers' workshops; the perforations of each stamp should be complete, and should have been neatly severed, and the gum on the back, unless it is so thick and crackly that it is a danger to the stamps, should be preserved intact. A used stamp should be selected for its lightness of postmark, though there are often times when a more heavily postmarked copy showing the date of use will be valuable evidence in the pursuit of historical researches. The colour of the used stamp should not be less good than that of an unused one, and the perforations should be all there. In the case of imperforate stamps it is desirable always to have as large margins round the printed impression as possible; while in all perforated stamps one should endeavour to secure well-centred copies--that is to say, copies in which the printed impression falls evenly between the perforations on all four sides.