For product the data is only stored in the database except from the search index that you can rebuild from BO\Settings\Search index.
For every file for the media they ave a column with named BlobUri that is the reference for the file that should be removed. And dependent how the URI is created it points to different directory in the common files folder. If the schema does not contain the work +storage then the file is below the Storage and maybe also in Storage_Cache folders and otherwise in the media folder.