In the main hall a bar with a real brass rail was set up, and stocked with gins and liquors and with cordials so long forgotten that most of his female guests were too young to know one from another.
(from The Great Gatsby)
Which words does the phrase "so long forgotten" modify in the sentence above? Does it mean just the cordials are so long forgotten or all the gins, liquors and cordials are also so long forgotten? How can you rewrite the sentence to emphasize each case?