Yes, Download Outlook Backup, save them to another drive and yoy can delete the ones on your HDD. You can access them by opening the backup file.
If they are taking up so much room I would be suprised, can't you save disc space any other way?
OnePlus 5 review
Alice Saey's mesmerising animation for Dutch singer Mark Lotterman
iPad Pro 10.5in (2017) review
Comment booster votre iPhone ?