Combine sugars, pineapple and juice, milk, corn syrup, salt, and butter in a 2-quart saucepan. Cook to 238 degrees F., stirring occasionally. Remove from heat and add marshmallows and vanilla. Mix together to melt marshmallow, then beat until mixture becomes heavy and creamy. Add nuts. Spread in a buttered 8-inch square pan. Cut into squares when cool and firm. Makes about 49 pieces.