A stain is read as a mark that will not easily go — a regret, a memory or a worry about reputation. Dream books look at whether it washes out or stays.
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.