Method of Treating Rubber Composition with Cure Inhibitor to Create Soft Skin in Golf Ball Core

A method of making a golf ball comprising the steps of:

• extruding a polybutadiene composition the form a cylindrical extrudate;
• cutting the extrudate to form an uncured polybutadiene preform;
• uniformly coating the preform with a cure-altering material comprising an organosulfur compound, an inorganic sulfide compound, or a metal-containing organosulfur compound;
• curing the coated preform to form a crosslinked core having an outer surface having a first hardness and a geometric center having a second hardness greater than the first to define a negative hardness gradient;
• centerless-grinding the cured core to form a uniformly-spherical core having increased surface roughness;
• forming an inner cover layer about the uniformly-spherical core;
• and
• forming an outer cover layer about the inner cover layer to form the golf ball.