Toenails are a part of the body few people look at, so dream books read them as small neglected matters. Tending them suggests putting your own groundwork in order.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.