What you want is if the file has not been accessed for 10+ days, delete. (-atime is last accessed, -mtime last mod, -ctime creationtime)

Make sure however your contraption reads the file, is actually changing atime, likely it is. Whenever the file is accessed, *ix changes the atime.

Login to your shell

Open your crontab # crontab -e

If you want it to run every hour:
59 * * * * /usr/bin/find /path/to/dir -type f -atime +10 -exec rm {} \;

that's an example, look up # man crontab