Data Cleansing

Hi,

Does the cleansing of Master Data Objects in MDM take place only during the initial upload to the Content Integrator ?

Do we use data cleansing in any other place ?

Also what exactly cleansing does. Duplicate removal seems to be a seperate service in MDM. If duplicate removal is not cleansing what exactly is cleansing ?

Can anybody please help me out or point me to some documents in SAPNET where I can find more information ?

With Best Regards,

Ramprasad.S