Data Purging approach

In order to improve database and Oracle apps performance, we are planning to purge very old data from our system.

What is the suggested approrach for this activity.

1) Which modules data should be purged first like the sequenece in which data should be purged.

2) List of all standard concurrent program to purge or archive data

3) What can be done to purge or archieve data which cannot be done through stadnard programs.