The present invention is directed to using methyl acetate from a vinyl acetate-based or a vinyl- or ethylene-alcohol based polymer or copolymer process directly for use in a methanol carbonylation production process to produce acetic acid, acetic anhydride, or a coproduction of each. Methyl acetate is a by-product of commercial polyvinyl-alcohol or alkene vinyl alcohol copolymer-based processes. Generally, this material is processed to recover methanol and acetic acid. Discussed herein is a cost-saving scheme to by-pass the methyl acetate processing at production or plant facilities and utilize the methyl acetate in an integrated methanol carbonylation unit. The scheme discussed eliminates an expensive hydrolysis step often associated with the polymer process.