Shampoo is read as washing out thoughts — clearing the mind and starting afresh. Dream books link it to wanting to rinse away a worry that has clung on.
Has this come up in your dreams before? What was going on in your life then?
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.