Deleting old instances

Pardon me if this is not the right forum.

I am trying to figure out a way to either programagically - or by standard use of XI R2 - delete old instances on a rolling 7 day basis.

I have a report that i want to run overnight. then the report is available to the user community ONLY through URL reporting.

I then want to clean up old instances.

Anything would be appreciated....

I am having troubles searching google/forums - probably because I dont have the right words...

-Dave Butz