Contact form: how to delete attached files from file system after form submission?

The working file attachment in a contact form looks like this:

-
  name: my-file
  label: 'Attach some files'
  type: file
  multiple: true
  limit: 5
  filesize: 6
  destination: user/data/files
  accept:
    - application/pdf
    - application/x-pdf
    - 'image/*'

Files are attached and sent with email. But those files are stored in a filesystem and they are growing.
Is there a default options to clear them or it could be done only with a CRON?