Methoxy groups heavily decorate the biopolymer lignin.  Much interest has been shown in converting this abundant form of biomass into useful chemicals (aside from fuel).  One step in such processing is demethylation.
  The demethylation of vanillin, a derivative of lignin, requires  and strong base.  Pulp and paper industry]] digests lignin using aqueous sodium sulfide, which partially depolymerizes the lignin.  Delignification is accompanied by extensive O-demethylation, yielding methanethiol, which is emitted by paper mills.