You can convert all Folder values that start with a hash mark ("#") to extent statements.  For example, you can convert <container type="Folder">#3</container to <physdesc><extent>3 folders.</extent></physdesc>.  To convert all folder values that start with a hash mark to extent statements, do the following:

• Open the approriate file in FACT.
• Select Refactoring > Run editorial XSLT. The Editorial Transformation dialog box will appear.
• Select "Convert all Folder Hashes to Extent" from the drop down menu.  Click OK.
• A second dialog box will appear, asking "This process involves the document being saved and re-opened. Do you wish to continue?"  Click Yes.
• The file will close and reopen.  Once the file has reopened, all Folder elements starting with the hash mark will have been replaced by extent statements. 
• Note: this operation cannot  be undone by Ctrl-Z.