Backing up an Oracle 10G Express on Windows 2000 Server
I don't have the 10g version of Express Edition installed, but if it is like the 11g version, then your first question is answered in the comments section of the Backup.bat file itself.  

For 11g this means the comments indicate that No cleanup script is needed because the script automatically keeps two backups in the Flash Recovery Area.  Whether there is a better method or not will depend on what your recovery requirements are.