If the link is not required any more then telnet into the router and issue Write erase cpmmand to delete the config and then issue reload command without saving the config.
Not usually something want in their routers. You might find APC or other UPS manufacturer has something where you can remote power down an attached device.
Naturally you'll have the problem of how to turn the device back on, you'll have to have out of band management sorted prior to turning the router off.
