Hi Badri,
Do you want to clean up the whole IFRS content or are you only wants to purge all Webi document type of objects in IFRS?
If you wants to purge Webi documents only, then you have to use RESTful Web Services SDKs (as you mentioned that you are currently using BI .1 SP04) & then follow a set of RESTful call sequence through which we can purge the Webi document data providers.
You have to automate/scripting the workflow of RESTful call sequence to purge all Webi documents present into Enterprise. (There is no ready made sample code present on SCN resources libraries which does the same).
Do you have an estimate that how much Webi documents are there in your Enterprise repository?
Regards,
Shailendra