Biff begins wearing his wife's perfume after her death, and he experiences a rush of sensory memory when he first puts it on:
But often he would uncork the bottle of Agua Florida and touch the stopper to the lobes of his ears or to his wrists. The smell mingled with his slow ruminations. The sense of the past grew in him. Memories build themselves with almost architectural order. (2.8.7)
Alice's perfume seems to symbolize the themes of memory in the book, but it also reminds us of Biff's own gender confusion. This is just one of many feminine touches he adopts after his wife dies. The perfume is sort of the gateway to Biff's gradual personal awakening, and he spends the entire latter part of the book figuring out who he is now and who he wants to be in the future. All that from a bottle of perfume. Who knew?