Data cleanse is used in conjunction with surveys and web capture forms. If either were configured to submit the data for approval, this is where you will find it. Use data cleanse to first view the submitted data, then approve it to be committed into your contact records.
Reporting - Data Cleanse
Select the criteria you wish to look for, the results will then be displayed below for you to approve. A contact update will not be made to the contact record until your approve the change.