A vacuum cleaner sucks up the hidden dust, so dream books read it as a thorough clear-out of things gathered in the corners. Its loud noise can also stand for an intrusion into calm.
Where in your waking life have you met something like this lately?
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.