In a large bowl, cream butter, oil and sugars until light and fluffy. Beat in egg and vanilla. Combine the flour, oats, baking soda, cream of tartar and salt; gradually add to the creamed mixture and mix well. Combine milk and vinegar; add to creamed mixture. Stir in chocolate chips and potato chips.
Drop by tablespoonfuls 2 in. apart onto ungreased baking sheets. Bake at 350° for 12-15 minutes or until golden brown. Remove to wire racks to cool.