Facebook Mobile Timeline Cleaner is an activity log scrubber that lets you take back control of your Facebook Timeline! It deletes your facebook comments/posts/likes etc in bulk.
This deletes content, use with care. You may loose your data permenantly. I am not responsible for lost data, facebook bans, thermonuclear war, or turning you into a newt.
To use it, install greasemonkey for firefox or tampermonkey for chrome. Install the script into greasemonkey or tampermonkey. Then navigate to your activity log page (profile -> "View activity log"). If the script is working it will add a new button called "Open All Times", just after "Friends" in the header. Click the new button and many tabs will open. Greasemonkey will load the script and begin deleting, hiding, and unliking content.