What are some examples of symbolism when Lady Macbeth is speaking in the play Macbeth?

There are several symbols of which Lady Macbeth speaks in the
play Macbeth.  In Act 2, Lady Macbeth says that she hears an owl shriek when
her husband is supposed to be murdering King Duncan.  She calls the owl the "fatal bellman" which
symbolizes the death of King Duncan. 

However, the more well-known
lines delivered by Lady Macbeth occur in Act 5 of the play.  Here, Lady Macbeth shows her guilt
over helping her husband commit murder early in the play.  She has learned that Lady Macduff and
her entire court have been killed, and Lady Macbeth cannot forgive herself for her role in her
husband's crime.  Here, Lady Macbeth says, "Out, out damned spot!" and makes like she is washing
her hands.  This symbolizes the "blood" that she sees on her hands and represents her
overwhelming sense of guilt.