I edited above post with a small guide how to use WinSCP
If you can leave the files or not depends on how big they are, if they have filled up all space on the system partition then same applications will not work properly. This can for instance be the reason why cron didn't work properly as you posted in the other topic. What you also can do to get rid of them is install the firmware one more time using the firmware upgrade option in the web interface. This will create a fresh system partition for you.