A method for processing a composite including reinforcing fibers held in a matrix of a plastic material or precursor for a plastic material for recovery of the reinforcing fibers, the method comprising: first treating the fiber-reinforced composite with a normally-liquid first solvent for material of the matrix to prepare a first treated solid residue comprising the reinforcing fibers, the first treating comprising contacting the fiber-reinforced composite with the first solvent and first dissolving at least a majority by weight of the matrix into the first solvent; and after the first treating, second treating at least a portion of the first treated solid residue comprising the reinforcing fibers with a second solvent of normally-gaseous material, having a different composition than the first solvent, to prepare second treated solid residue, the second treating comprising contacting the at least a portion of the first treated solid residue with the normally-gaseous material under conditions of temperature and pressure at which the normally-gaseous material is in a form of a liquid or supercritical fluid; and wherein: the normally-liquid first solvent is in the form of a liquid when at conditions of 0.1 MPa pressure and 25° C temperature; and the normally-gaseous material is in the form of a gas when at conditions of 0.1 MPa pressure and 25° C temperature; the second solvent is a solvent for the first solvent; and the second treating comprises dissolving into the second solvent a residual portion of the first solvent associated with the first treated solid residue following the first treating. first treating the fiber-reinforced composite with a normally-liquid first solvent for material of the matrix to prepare a first treated solid residue comprising the reinforcing fibers, the first treating comprising contacting the fiber-reinforced composite with the first solvent and first dissolving at least a majority by weight of the matrix into the first solvent; and after the first treating, second treating at least a portion of the first treated solid residue comprising the reinforcing fibers with a second solvent of normally-gaseous material, having a different composition than the first solvent, to prepare second treated solid residue, the second treating comprising contacting the at least a portion of the first treated solid residue with the normally-gaseous material under conditions of temperature and pressure at which the normally-gaseous material is in a form of a liquid or supercritical fluid; and wherein: the normally-liquid first solvent is in the form of a liquid when at conditions of 0.1 MPa pressure and 25° C temperature; and the normally-gaseous material is in the form of a gas when at conditions of 0.1 MPa pressure and 25° C temperature; the second solvent is a solvent for the first solvent; and the second treating comprises dissolving into the second solvent a residual portion of the first solvent associated with the first treated solid residue following the first treating. the normally-liquid first solvent is in the form of a liquid when at conditions of 0.1 MPa pressure and 25° C temperature; and the normally-gaseous material is in the form of a gas when at conditions of 0.1 MPa pressure and 25° C temperature; the second solvent is a solvent for the first solvent; and the second treating comprises dissolving into the second solvent a residual portion of the first solvent associated with the first treated solid residue following the first treating.