Is it possible to somehow to clean N9 (do factory reset) without touching the screen?

To problem is, that touchscreen on my N9 stopped responding completely. Before letting the phone out of my hands, I'd like to reset it to factory settings, or at least clean all my passwords. Is it possible?

I have working ssh access and I have some linux knowledge, so I can do some basic things like deleting files or installing packages. I also tried connecting using VNC, but I can't control the phone from my pc. I successfully started x11vnc on the phone, I connected using TightVNC and VNC Viewer from RealVNC, I can see the screen in both of them (and when I wake up phone using phone button, lock screen is shown on my pc), but I can't control the phone, it is completely unresponsive to all mouse and keyboad inputs I tried. I don't know, if it is problem with the VNC server or client.

Thanks in advance for any help.

Flashing the device with "--erase-user-data=secure" option will delete everything in the device. There's no need to use the screen at all to do it.

Ok, I'm an idiot. Before reading your answer, I was playing with VNC. I found it, that it works, only problem is that swipe doesn't work, so no unlocking of screen and no scrolling. I overcome the unlocking by restarting the phone. Then I got into setting and while I was trying to scroll, I accidentally activate plane mode. Now obviously can't connect over wifi. Guess I'm screwed, am I not? I surely have usb cable and working buttons, but it seems to me it is no help for me. Any ides, like some secret master button combination?

C'mon.

juiceme said everything that needed to be said.
Some more spoons:
https://wiki.maemo.org/Flashing_N9
http://talk.maemo.org/showthread.php?t=82693

Sorry, I didn't get it at first time. Downloading firmware right now, thanks to both of you

---- EDIT ----

Flash went fine without problem. Thanks again

are you selling your device giving it away is it 16 or 64gb