TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The step of contacting the spent ion-exchange resin with the alcohol ion-exchange regenerant involves leaving residual alcohol ion-exchange regenerant in the low metal, water-containing biomass-derived pyrolysis oil. The step of contacting the spent ion-exchange resin with the alcohol ion-exchange regenerant involves contacting the spent ion-exchange resin with an alcohol recovered from azeotropic distillation of metal- and water-containing biomass-derived pyrolysis oil, with an alcohol recovered from azeotropic distillation of low metal, water-containing biomass-derived pyrolysis oil, and/or with an alcohol from an alcohol source. The step of contacting the spent ion-exchange resin with the acidic ion-exchange regenerant involves contacting the spent ion-exchange resin with a recovered acidic aqueous stream from distillation of a metal- and water-containing biomass-derived pyrolysis oil, with a recovered acidic aqueous stream from distillation of a low-metal, water-containing biomass-derived pyrolysis oil, and/or with an acid from an acid source. The step of contacting the spent ion-exchange resin with the alcohol ion-exchange regenerant comprises selecting the alcohol ion-exchange regenerant from methanol, ethanol, acetone and/or 2-butanone. The method further involves the step of purging water through the spent ion-exchange resin between contacting the spent ion-exchange resin with an alcohol ion-exchange regenerant and contacting the spent ion-exchange resin with an acidic ion-exchange regenerant. The step of contacting the spent ion-exchange resin with an acidic ion-exchange regenerant to recharge the acidic ion-exchange resin to produce a regenerated acidic ion-exchange resin comprises returning the spent ion-exchange resin to an acidic protonated form in which the active groups is sulfonic group of formula SO3H. The method further involves the step of rinsing the acidic ion-exchange regenerant from the recharged acidic ion-exchange resin prior to the step of contacting the metal- and water-containing biomass-derived pyrolysis oil with the regenerated acidic ion-exchange resin. The method further involves the step of recycling the spent ion-exchange regenerants. The step of recycling the spent ion-exchange regenerants involves reusing the alcohol ion-exchange regenerant as an azeotrope-forming liquid in the azeotropic distillation process, as an alcohol ion-exchange regenerant to remove residual oil from the spent ion-exchange resin, to regenerate a spent ion-exchange resin, and/or as the alcohol source. The step of recycling the spent ion-exchange regenerants involves reusing the acidic ion-exchange regenerant to regenerate the spent ion-exchange resin in another cycle, and/or to be used in a pyrolysis reactor. EXAMPLE - No suitable example is given.