touch screen failed on my android tablet--my email logged in Touch screen failed on my android tablet. I requested for replacement. The problem is that all my accounts are signed in.I can't give my device back as all accounts are signed in.lets say they repaired the device then they can have access to my gmail account. How can I log off from that tablet since touch is not working. Is there any way that I can do to prevent others from looking into my gmail account and accessing it.can I log off it from my laptop?? please help me. Thanks in advance.
Change the password on your Google account from the web interface. Next time your device tries to connect, it'll be signed out.

You could also boot into the recovery (the way to do this depends on what tablet you have), and factory-reset the tablet from there. The recovery menu is operated by the hard buttons, not the touch screen, so you should still be able to do this.