Processing fiber-reinforced composite to recover reinforcing fibers includes first treating the composite with a normally-liquid first solvent for material of the matrix followed by second treating of solid residue including reinforcing fibers from the first treating with a normally-gaseous material contacted with the solid residue under conditions of temperature and pressure at which the normally-gaseous material is in a liquid or supercritical fluid form. Treating a crude product including released reinforcing fibers and residual material of the matrix and/or fiber sizing includes first converting a normally-gaseous substance from a fluid form to a solid form and thereafter second converting the solid form to a gaseous form, to assist dislodgment of such residual material.