Can I automatically recycle files once they have been downloaded?

Yes. Go to ‘Account Settings -> Password/Profile’.

At the bottom left of the page, you may need to scroll to the bottom, you will see the options:

Never - I'll delete them myself
1 day
7 week
2 weeks
3 weeks
1 month

To change when a file is recycled.  Be sure to select "Save" to save the change.