I realized tonight that in my dreams I can sometimes remember old dreams that I have forgotten. It is as if our dreams to some degree share the same memory space, a a space which we have limited access to when we are awake.
Lucid dreaming can allow us to both test this theory and use it to help us:

Find in your dream journal a dream that you recalled very few details from ( and wrote only those few details in the journal ), but this dream interest you very much and you want to try to remember more details from it. Before attempting to lucid dream assert in your mind that when you LD you will try to remember this dream, and if you succeed in LDing than do your best to recall it.