Pellicles such as films, sheets, bands, straws, caps and tubes of regenerated cellulose or lowly etherified cellulose ethers are softened by impregnating them with a water-soluble organic sulphoxidate of the formula X = S = On, in which n is either 1 or 2, and X represents one or two organic radicals in which there is a carbon atom directly attached to the sulphur atom. The softening agent may be a sulphoxide or a sulphone. It is regarded as water-soluble if it dissolves to the extent of at least 2 per cent by weight in water at a temperature not higher than 60 DEG C. Preferably, each organic radical, attached to the sulphoxy group, is a hydrocarbon residue containing at least one water-solubilising substituent or linkage, e.g. the groups -OH, -O-alkyl, -NH2, -COOH, -SO3H, -NH-, -CO- and -CO-NH-. The sulphoxide or sulphone may be a straight or branched chain compound, or a heterocyclic compound with the sulphur atom forming part of the ring. The sulphoxide or sulphone may be used in conjunction with other softening agents for regenerated cellulose materials, e.g. glycerine, ethylene glycol, formamide, glycol polyformal, N-(2 : 3-dihydroxypropyl)-hydroxyacetamide. A mixture of sulphoxides or sulphones may be used, e.g. 2 : 5-dihydrothiophene-1 : 1-dioxide and diethyl sulphone, or 3-methoxytetrahydrothiophene-1 : 1-dioxide and methyl butyl sulphoxide. Preferably, the regenerated cellulose materials are impregnated with an aqueous solution of the softening agent while they are still in the gel state following coagulation and regeneration, but already dried materials may be re-wetted and then impregnated with the solution of the softening agent. Impregnation may be effected by immersion or by spraying. Dyestuffs may be incorporated in the softening bath. In an example, viscose is extruded to form a continuous film which passes through coagulating and regenerating solutions, purifying and washing baths, and then through an aqueous solution of glycerine and the methanol adduct of 2 : 5-dihydrothiophene-1 : 1-dioxide, and then over drying rolls. The softened film may be used for wrapping cotton goods such as bed sheets and p pillow-cases. Instead of the methanol adduct, there may be used the ethanol, isopropanol, ethylene glycol, or glycerine adduct of 2 : 5-dihydrothiophene-1 : 1-dioxide. In other examples, a regenerated cellulose film is impregnated with an aqueous solution of beta-ethylsulphinyl tetra-methylene cyclic sulphone, 3 : 4-dimethoxy - tetrahydrothiophene - 1 : 1 - dioxide, diethyl sulphone, 2 : 5-dihydrothiophene-1 : 1-dioxide, or the addition product of water with 2 : 5-dihydrothiophene-1 : 1-dioxide. In another example, a regenerated cellulose tube is made by joining several viscose streams to form an annular stream which is then passed into a coagulating liquid. The purified tube is impregnated with a solution of the methanol adduct of 2 : 5-dihydrothiophene-1 : 1-dioxide. The tube is cut into short lengths which are used as secondary closures or seals for bottles. In other examples, regenerated cellulose film is impregnated with di - b - hydroxy - ethyl sul - phoxide, 2 : 21 - (methylene disulphinyl-) di - ethanol, ethyl - a - hydroxypropyl sulphoxide, ethyl-2 : 3-dihydroxy-propyl sulphoxide, methyl butyl sulphoxide, or di-ethyl sulphoxide. The methanol adduct of 2 : 5-dihydrothiophene-1 : 1-dioxide is made by causing methanol to react upon 3,4-dehydrocyclotetramethylene sulphone, preferably in an alkaline medium. The ethanol, isopropanol, ethylene glycol and glycerine adducts are made similarly. Beta-ethyl-sulphinyl tetramethylene cyclic sulphone is made by causing ethanethiol to react with 2 : 5-dihydro-thiophene-1 : 1-dioxide, preferably in alkaline medium, followed by oxidation of the resultant product with a solution of hydrogen peroxide. The compound 3 : 4-dimethoxytetrahydrothiophene-1 : 1-dioxide is made by reacting 2 : 5 - dihydrothiophene - 1 : 1 - dioxide with a chlorinating agent consisting of chlorine and absolute methanol at 0 DEG C. and subjecting the intermediate compound, 3 - chloro - 4 - methoxy - tetrahydrothiophene-1 : 1 - dioxide to the action of methyl alcoholic potassium hydroxide. Diethyl sulphone is obtained by refluxing diethyl sulphide with an excess of hydrogen peroxide solution. The compound 2 : 5-dihydrothiophene-1 : 1-dioxide is obtained by reacting sulphur dioxide with butadiene hydrocarbons in the presence of an antipolymerization catalyst, e.g. pyrogallol or other polyhydric phenol. Liquid sulphur dioxide may be used and the hydrocarbons may be dissolved in benzene. Di - b - hydroxy - ethyl sulphoxide is prepared by oxidising di-(b -hydroxy-ethyl) sulphide with hydrogen peroxide at 70 DEG C. The compound 2 : 21-(methylene disulphinyl-)di-ethanol is made by reacting 2 mols. of thioethylene glycol with 1 mol. of formaldehyde in presence of an acidic catalyst, and oxidising the product by means of hydrogen peroxide. Ethyl-a -hydroxypropyl sulphoxide is made by reacting ethanethiol with allyl alcohol in presence of mercuric acetate and oxidising the product with hydrogen peroxide. Ethyl-2 : 3-dihydroxypropyl sulphoxide is prepared by reacting ethanethiol with glycerine chlorhydrin in presence of alkali and oxidising the product with peroxide. Methyl butyl sulphoxide is obtained by the action of methyl chloride on butanethiol under alkaline conditions, and oxidising the product with peroxide. Specifications 211,446, [Class 2 (ii)], and 552,498 are referred to. The Specification as open to inspection under Sect. 91 comprises also the treatment of artificial filaments and sponge-material. This subject-matter does not appear in the Specification as accepted.