Electro-neutral salts are prepared by reacting in an aqueous medium an anionic surface-active compound containing an aliphatic radical having at least 6 carbon atoms and containing a sulphuric acid ester or sulphonic acid group with an organic cationic surface-active anion compound containing an aliphatic radical having at least 4 carbon atoms. The salts are used to increase the water-solubility of anionic surface-active agents in the cold and when these anionic compounds are of the above-specified type, the electro-neutral salts may be prepared therefrom in situ by adding to the anionic compound in water, an amount of the cationic compound which is not more than 50 per cent of the weight of the anionic compound (see Group IV (c)). Specified electro-neutral salts are N-dodecyl pyridinium octyl sulphate from N-dodecyl pyridinium chloride and octyl sodium sulphate, N-octadecyl pyridinium C7 - 9 alkyl sulphates from N-octadecyl pyridinium chloride and C7 - 9 alkyl sodium sulphates, dimethyl hexadecyl phosphonium dodecyl sulphate from dimethylhexadecyl phosphonium chloride and dodecyl sodium sulphate, the salt from N-dimethyl-N-benzyl amino-acetic acid dodecyl amide chloride and octadecyl sodium sulphate and the salt from N-benzyl piperidinium acetic acid decyl amide chloride piperidinium acetic acid decyl amide chloride and octadecenyl sodium sulphate. In examples illustrating the enhancing of the solubility of the anionic compounds (1) a small amount of dodecyl pyridinium chloride is added to C12-18 alkyl sodium sulphates in water; similarly, (2) dodecyl pyridinium sulphate is added to aqueous sodium dodecyl benzene sulphonate; or (3) to aqueous sodium oleyl sulphate. Specifications 316,090, 358,202, [both in Class I (i)], 442,466 and 641,297, [both in Group III], are referred to.ALSO:The water-solubility of organic anionic surface-active compounds in the cold is increased by contacting the active compounds in aqueous medium with an organic electroneutral salt obtained by reacting an organic cationic surface-active onium compound containing an aliphatic radical having at least 4 carbon with an organic anionic surface-active compound containing an aliphatic radical having at least 6 carbon atoms and a sulphuric acid ester or sulphonic acid group, the amount of the cationic compound being not greater than 50 per cent, preferably 5 to 30 per cent, by weigth of the total content of organic anionic surface-active compound in the aqueous medium. The electroneutral salt may be added to the anionic compound in the aqueous medium or the salt may be formed in situ when the anionic compound to be solubilized is one of the class specified above for the electroneutral salt formation. The anionic compounds whose solubility may be increased include the soluble inorganic or organic salts of fatty acids, wax acids, resin acids, naphthenic acids, condensation products of high molecular weight carboxylic acids or sulphonic acid halides with proteins acidsulphuric and phosphoric esters, alkyl sulphonic acids, alkyl benzene and naphthalene sulphonic acids and dialkyl aryl disulphonimide or sulphocarbon imides; the hydrocarbon radicals of these compounds may contain substituents such as hydroxyl, mercapto or amino groups or may be interrupted by oxygen, sulphur or nitrogen atoms or by such groups as ester carbonamide or sulphonamide groups. Examples of such anionic acids include octyloxyacetic acid, hexadecylmercapto acetic acid, C-alkyl cresoxy acetic acids, dodecyl sulphuric acid, ester, oleyl sulphuric acid ester, the sulphuric or phosphoric acid ester of ethylene glycol mono-octyl ether, the mono- or di-sulphuric or phosphoric acid ester of glycerine mono-stearic acid ester, the phosphoric acid ester of decandiol monoacetate, the o -hexyl thioether of octyl thiosulphuric acid ester, N-butyl-N-dodecyl sulphhamic acid N-oleyl N-methyl-aminoethane b -sulphonic acid, steoryloxy-ethane b -sulphonic acid, N-octyl sulphone sulphanilic acid, o -cyclohexyl ether of decane sulphonic acid, sec.octylphenyl benzyl ether 41-sulphonic acid, C6-18 alkyl benzene sulphonic acids 2-isoamyl cresoxy benzoic acid, 5-sulphonic acid, 1-sec. hexylphenoxy-2-acetylamino benzene-4-sulphonic acid and sulphonated cresoxy acetic aicd dodecyl amide. Specified cationic active compounds for use in forming the electro-neutral salts include trimethyl butyl ammonium bisulphate trimethyl dodecyl ammonium chloride, dimethyl dodecyl benzyl ammonium chloride, hexyl quinolinium chloride, octadecoxy carbomethyl trimethyl ammonium chloride, naphthenoxy carbomethyl quinolinium chloride, octadecylaminocarbomethyl trimethyl ammonium chloride, octadecylthio methyl triethyl ammonium bisulphate, octadecyloxycarbamino methyl pyridinium metho-sulphate and correspondingly constituted compounds having a quaternary phosphorus or arsenic atom or a ternary sulphur atom. Preformed electroneutral salts mentioned are N-dodecyl pyridinium octyl sulphate from N-dodecyl pyridinium chloride and octyl sodium sulphate, N-octadecyl pyridinium C7-9 alkyl sulphates from N-octadecyl pyridinium chloride and C7-9 alkyl sodium sulphates, dimethyl hexeadecyl phosphonium dodecyl sulphate from dimethyl-hexadecyl phosphonium chloride and dodecyl sodium sulphate, the salt from N-dimethyl-N-benzyl-aminoacetic acid dodecyl amide chloride and octadecyl sodium sulphate and the salt from N-benzyl piperidinium acetic acid decyl amide chloride and octadecyl sodium sulphate. The solubilityenhancing compounds may be added to any aqueous preparation or treating bath containing an anionic surface-active compound e.g. in hair washes, cosmetics, washing solutions and aqueous media wherein the anionic compounds themselves are being used to increase the solubiuity of other substances such as dyes or pigments. In examples (1) dodecyl pyridinium chloride is added to C12-18 alkyl sodium-sulphates in water yielding a mixture comprising 24 per cent alkyl sodium sulphates, 6 per cent cationic compound and 20 per cent sodium sulphate, which is then atomized and dried; it may be used for washing linen; (2) the turbidity of a solution of sodium dodecyl benzene sulphonate or (3), of sodium oleyl sulphate is reduced by addition of a minor amount of dodecyl pyridinium sulphate. Specifications 316,090, 358,202 [both in Class 1(i)], 442,466. [Group IV] and 641,297 are referred to.ALSO:The water-solubility of an organic anionic washing agent in the cold is increased by contacting the compound in aqueous medium with an organic electroneutral salt obtained by reaction between an organic anionic surface-active compound containing an aliphatic radical having at least 6 carbon atoms and a sulphuric acid ester or sulphonic acid group, and an organic cationic surface-active onium compound containing an aliphatic radical having at least 4 carbon atoms, the amount of said cationic compound being not greater than 50 per cent by weight of the total content of organic anionic surface-active compound in the medium. The electroneutral salt may be preformed or it may be prepared in situ when the anionic compound whose solubility is to be increased is one of the class specified above for the electroneutral salt formation. Anion-active substances which may be rendered more soluble include water-soluble salts of the higher fatty acids, wax acids, naphthenic acids, resin acids, octyloxylacetic acid, hexadecylmercapto acetic acid, dodecyl sulphuric acid ester, oleyl sulphuric acid ester, o -butyl ether of decyl sulphuric acid ester, the mono- or di-sulphuric or phosphoric acid ester of glycerol mono-stearic acid ester, the o -hexyl thioether of octyl thio-sulphuric acid, N-butyl-N-dodecyl sulphamic acid, N-oleyl-N-methyl aminoethane-b -sulphonic acid, stearyloxyethane b -sulphonic acid, N-octyl sulphone sulphanilic acid, sec. octylphenyl benzyl ether-41-sulphonic acid, C6-18 alkyl benzene sulphonic acids, 1-sec. hexylphenoxy-2-acetylaminobenzene-4-sulphonic acid, cresoxy acetic acid dodecyl amide sulphonic acid and diethyl aryl disulphonimides or sulpho carbon imides. Specified electroneutral salts are N-dodecyl pyridinium octyl sulphate (from N-dodecyl pyridinium chloride and sodium octyl sulphate), N-octadecyl pyridinium alkyl sulphates (from N-octadecyl pyridinium chloride and C7-9 alkyl sodium sulphates), dimethyl-hexadecyl phosphonium dodecyl sulphate (from dimethyl-hexadecyl phosphonium chloride and dodecyl sodium sulphate), the salt from N-dimethyl-N-benzyl amino-acetic acid dodecyl amide chloride and octadecyl sodium sulphate and the salt from N-benzyl-piperidinium acetic acid decyl amide chloride and octadecenyl sodium sulphate. Other onium compounds specified for use in forming the electroneutral salts include trimethyl butyl ammonium bisulphate, trimethyl octadecyl ammonium methosulphate, hexyl quinolinium chloride, octadecoxy carbomethyl trimethyl ammonium chloride, naphthenoxy carbomethyl quinolinium chloride, octadecylamino carbomethyl trimethyl ammonium chloride, octadecyl thio methyl triethyl ammonium bisulphate, octadecyl carbamino methyl pyridinium chloride and corresponding compounds with a quaternary phosphorus or arsenic atom or a ternary sulphur atom. The solubility-enhancing compounds may be added to any aqueous preparations or treating solutions containing the anionic compounds, e.g. washing solutions and hair washes. The resulting aqueous mixtures may be made up into pastes or various solid forms, if desired with the usual soap additions. In examples: (1) a mixture suitable for washing linen is made by adding a small amount of dodecyl pyridinium chloride to C12-18 alkyl sodium sulphates in water; the resulting solution may also be atomized and dried; (2)-(3), dodecyl pyridinium sulphate is used similarly to reduce the turbidity of dilute solutions of sodium dodecyl benzene sulphonate and sodium oleyl sulphate respectively. Specifications 316,090,