Beat butter, sugar, brown sugar, and vanilla until blended. Add eggs and milk; beat well. Stir together flour, cocoa, baking soda, and salt; gradually add to butter mixture, blending well. Stir in chocolate chips. Shape dough into 1-inch balls. Place on ungreased cookie sheet. Bake 10-11 minutes at 350. Cool 1 minute, remove to wire rack. Press Kisses in center of each cookie. Makes about 4 dozen cookies.