Today we simply go to the store and purchase artificial sponges and on occasion ocean grown real sponges. My parents lived in Key West, FL. for many years and my Mom would purchase many sponges from the sponge fisherman and she would work for days cleaning these sponges. Below are some possible procedures your characters might have used to bleach their sponges.
On Bleaching Sponge. By M. Vogel, of Munich.*
Although sponge, in its chemical nature, very much resembles silk and wool, yet it cannot be bleached in exactly the same manner as those substances. M. Vogel was convinced that the bleaching of it would be the more difficult, as the action of the vapour of burning sulphur upon it reduces it so considerably, or, as we may say, almost to nothing; whilst both silk and wool, as is well known, are bleached by this means in a most complete manner. The finer the sponges, the more easily they are bleached. The following method has succeeded extremely well for this purpose:—
The sponges must first be sufficiently steeped in cold water; for if they were to be put into either boiling or even warm water, it would produce a most destructive effect upon them; as they would shrink, their pores would be closed, they would become hard, and it would be impossible to bleach them afterwards.
But if the sponges are steeped in cold water, which should be changed every three or four hours, and if at each time it is changed they were submitted to so strong a pressure as to be entirely freed from the water, at the expiration of five or six days they would become sufficiently washed, and be prepared for the bleaching.
If, as it frequently happens, the sponges retain, in their interior, small calcareous stones, which it might be supposed could not be extracted without tearing them or beating them to pieces, yet it is easily effected by allowing them to steep for 24 hours in muriatic acid, diluted with 20 parts of water: this produces a slight effervescence, from the extrication of the carbonic acid gas; and the calcareous concretions disappear, being dissolved in the most complete manner.
Then, after having been very carefully washed, the sponges are thrown into a solution of sulphurous acid, of the specific gravity of 1,024; or which marks about 4" on the areometer of Beaume. The following is the best manner of preparing this acid:—Put into a glass retort, one pound of pulverized charcoal, and one pound of concentrated sulphuric acid; and, by means of a bent tube, convey the gas, which is extricated, into a vessel, where it may be combined with eight pints of water, according to the Bavarian measure.t
The immersion of the sponges in this acid is to be continued for eight days; but during this time they are to be repeatedly submitted to the action of a press; and, lastly, they are allowed to remain 24 hours in running water.
When the sponges have thus been washed in a sufficient quantity of running water, they may be sprinkled with rose or orange-flowerwater, for the purpose of communicating to them an agreeable odour; after which, they must be allowed to dry gradually in the open air.
Source: The Franklin Journal and American Mechanics' Magazine ©1828
There arc several methods by which sponges may be bleached, and thus rendered attractive and salable. The two best are presented below. Any druggist of ordinary skill can bleach his sponges, and thus double t heir value.
1. First clean, wash, and squeeze out the sponges; then dip them into a two-per-cent solution of permanganate of potassium. Here they become quite brown (from separated manganic oxide). After ten minutes, they are taken out, washed in water, again well pressed, and then dipped into a two-per-cent solution of oxalic acid [we prefer diluted sulphuric (1 : 20) or diluted hydrochloric acid (1 : 15)], in which they become perfectly white. Success mainly depends on the soaking in the permanganate solution. If they are macerated too short a time, they do not become thoroughly white; if too long, they are apt to become rotten.
2. First clean the sponges by immersing them in diluted hydrochloric acid; then soak them in the bleaching liquid, composed of hyposulphite of sodium one part, water twelve parts, and hydrochloric acid two parts. After some time they are removed and well washed. To the last wash-water a little glycerine is added in order to preserve the sponges soft. The liquid is best pressed out by passing the sponges through a clothes-wringer.
3. Toilet sponges which have been in use often become peculiarly slimy, fatty, and almost useless, owing to some action of the soap. Mere washing in distilled water does not remove the difficulty. It may be overcome byusing fused chloride of calcium. The sponge is pressed as much as possible, placed on a plate, the powdered chloride- of calcium sprinkled upon it, and allowed to deliquesce upon the sponge. After about half an hour the sponge may be washed in water, and dried, when it will become white.
Though all the above processes furnish satisfactory results, yet the following combination and modification of two of the above processes will be found to work better still.
Soak the sponges, previously deprived of sand and dirt by beating and washing, in a one-per-cent solution of permanganate of potassium; then remove them, wash them thoroughly with water, and press out the water; next put them into a solution of one-half pound of hyposulphite of sodium in one gallon of water to which one ounce of oxalic acid has been added, and leave them in the solution for fifteen minutes; finally take them out, and wash them thoroughly.
By this treatment the sponges are rendered perfectly white. Many sponges contain a more or less dark-colored, brownish core. If treated only with permanganate and acid, the core is cither not bleached at all, or, if it has been somewhat bleached, the tint is apt to grow again darker. By the above modification, every portion of the sponge is rendered white, and remains so.
Source: The Popular Science News and Boston Journal of Chemistry ©1883
Sponge.—(1) Saturate in a quart of buttermilk for 24 hours, and rub between the hands. (2) Soak in dilute muriatic acid (1 acid to 1J water) for 12 hours, wash well with water, to remove lime, then immerse it in a solution of 2 lb. hyposulphite of soda in 12 lb. water, to which 2 lb. muriatic acid has been added a moment before. After it is sufficiently bleached, remove, wash again, and dry. (3) Soak for several days in cold water, renewing the water and squeezing the sponges occasionally. Then wash in warm water, and put into cold water acidulated with hydrochloric acid. Next dry, take out, and wash thoroughly in soft water; then immerse in an aqueous sulphurous acid (sp. gr. 1 • 034) for a week. Afterwards wash in plenty of water, squeeze, and allow to dry in the air. (4) Soak in dilute hydrochloric acid to remove the lime, then wash in water, and place for 10 minutes in a 2 per cent. solution of potassium permanganate. Their brown appearance on removal from this is due to deposition of manganous oxide, which may be removed by steeping for about 2 minutes in a 3 per cent. solution of oxalic acid, to which a little sulphuric acid has been added. As soon as the sponges appear white, they are washed out in water to remove the acid. Very dilute sulphuric acid may replace the oxalic acid. (5) First wash in tepid water, and then in a solution of hydrochloric acid (o «. per litre = 5 fl. dr. per 7 pints), which frees the pores from carbonate of lime; next immerse for 24 hours in a solution composed of 5 pints hydrochloric acid in 100 of water, with addition of 6 pints hyposulphite of soda.
Source: Workshop Receipts ©1883