Formerly this was done by skinning the pearl, _i.e. _, removing the outer skin by peeling it carefully off with the edge of a sharp knife, an unsatisfactory method at best, as the under skin may not be good and if all the outer skin is not taken off, the broken edges of the layers composing the skin, mar the luster and color when the pearl is worn. Few also succeed in removing a skin without scratching the new one disclosed by its removal. Pearls having a decidedly bad outer skin with a good one under it, can only be materially improved by removing the bad skin, but owing to the liability of finding equally bad imperfections underneath, or irregularities which would necessitate the removal of several skins with a consequent loss of size and weight, pearls with minor imperfections or lack of luster are now slowly rubbed between the fingers, the abrasion being assisted by various substances which differ with the judgment and experience of the operator, the preparation being in all cases kept secret by the expert using it. Many fine pearls which have lost their pristine luster are now considerably improved by this method, and without the dangers involved and the necessary loss of weight, consequent on peeling. Large numbers of poor or imperfect pearls are scraped or otherwise doctored by the traders and speculators at the fisheries. These men acquire such pearls at a slight cost, and by various methods fix them so that by mixing them in lots with good pearls, they often make large profits. They also mix in many cracked pearls. This is done more often at Margarita and the other Venezuelan fisheries where the proportion of cracked pearls is greater than in the Indian and South Sea fisheries. The skins of a pearl may also be removed by the application of weak acids, but this method requires careful and expert handling or the acid will act irregularly and leave the surface, if improved in luster, uneven and pitted. Few important fresh-water baroques and irregular pearls leave the west without receiving the attention of the speculators through whose hands they pass, and the scraping is often very roughly done. Rough and discolored projections are broken or filed off and then scraped over with a knife edge. While fresh, the broken skin edges left thus will often pass unnoticed by a careless buyer, but they become discolored and dead later. Unless one buys of a dealer in whom implicit confidence may be placed, not alone for honesty but for his knowledge of pearls, it is better to examine all pearls under a glass before purchasing.