An indulgence, applicable only to the Souls in Purgatory, is granted to the faithful, who devoutly visit a cemetery and pray, even if only mentally, for the departed. The indulgence is plenary each day from November 1-8; on other days of the year it is only a partial indulgence.
The plenary indulgence is earned under the usual conditions: sacramental confession (within 20 days before or after), one Eucharistic Communion for each visit (20 days before or after), and prayer for the Pope’s intentions while detached from sin.
The Ostende Blog - Fr Christopher Young 