If there is a condition attached to the contribution then retain permanently. Retain for six years after the date of filing for tax audits then dispose of.
26 U.S.C. 6501
Confidential destruction is required. Paper must be shredded, pulped, or incinerated; electronic records must be overwritten or the storage media physically destroyed. Deletion of information in computer files or on electronic storage media is not sufficient.
Last Updated: December 31, 2008