The invention is directed to a method of making a golf ball comprising the steps of: providing a core comprising at least one layer; forming a cover about the core comprising at least one cover layer comprising a cover inner surface and a cover outer surface and having a thickness D; treating the cover outer surface with a fatty acid and/or fatty acid salt composition and forming a treated cover region which extends inward from the cover outer surface a penetration depth DCTr, an untreated cover region being disposed between the cover inner surface and the treated cover region and having a depth (DCUTr)=(D)−(DCTr); wherein the treated cover region has a hardness α and the untreated cover region has a hardness β different than the hardness α. In another embodiment, the method may alternatively comprise the step of treating the cover inner surface with a fatty acid and/or fatty acid salt composition and forming a treated cover region which extends inward from the cover outer surface a penetration depth DCTr, an untreated cover region being disposed between the cover inner surface and the treated cover region and having a depth (DCUTr)=(D)−(DCTr); wherein the treated cover region has a hardness α and the untreated cover region has a hardness β different than the hardness α. In yet another embodiment, the method of making the golf ball comprises the steps of providing a core comprising at least one layer; forming a cover about the core comprising at least one cover layer comprising a cover inner surface having a hardness β and a cover outer surface having a hardness α; treating the cover outer surface with a fatty acid and/or fatty acid salt composition and forming a treated cover outer surface comprising the fatty acid and/or fatty acid salt composition wherein the treated cover outer surface has a hardness α′ different from hardness α; and wherein hardness β is different than at least one of hardness α and hardness α′.