washing or rinsing iterations can be performed with fresh water or fresh aqueous dilute acid solution e g not comprising any solubilized or dissolved calcium salts in various embodiments the calcium salt can be removed fresh water e g diluting the slurry of solid constituents in aqueous dilute acid solution with fresh water in the range of 1 to 10 fold in some embodiments leaching techniques e g as documented in treybal robert e u201c mass transfer operations 1980 mcgraw hill book company 3rd edition u201d are applied such leaching techniques can reduce the amount of fresh water to slurry from 0 5 to 5 using multiple stages of extraction after dilute acid treatment and subsequent wash removal of the water soluble calcium salt there is a mixture of solids in a combination of nylon polypropylene sbr and embedded caco 3 5 dissolving the nylon and other materials in an acid solvent that dissolves nylon the slurry of undissolved and insoluble constituents e g undissolved nylon insoluble polypropylene and sbr separated from the solubilized or dissolved calcium salts is dissolved in an acid solvent that dissolves nylon but does not dissolve pp or sbr suitable acid examples include without limitation formic acid sulfuric acid phosphoric acid hydrochloric acid acetic acid nitric acid and mixtures thereof the acid used as the solvent does not need to be the same acid that is used for the pretreatment e g for removal of the surface exposed calcium carbonate in various embodiments the acid solvent can be a lower alkyl aliphatic carboxylic acid for example an aliphatic carboxylic acid containing from 1 8 carbons for example 1 6 1 4 or 1 3 carbons branched or straight in the form.