Data cleaning is the process of improving data files and
databases by removing or correcting data that may be incorrect,
out of date, incomplete, duplicated, or irrelevant.
Personal data can go out of date very quickly unless
it is maintained; to keep your data up to date it should be regularly
cleaned, especially before mailing out marketing materials.
Sending communications using inaccurate consumer data can
cost you both money and customers; nobody wants to receive a mailing
where their personal information is wrong.