Here's the stuff! You can buy it almost anywhere. Wal-Mart, Target, Staples, or any other store that sells office supplies.
Just a micro-ball of it is all you need! It lasts forever if you re-use he same piece over and over. I've had this pack for months now and used it on dozens of pens.
There's a thin ball of it on the cap of the pen. That's all it takes, then you just need to hide it from the camera veiw when you take your pictures.
I hope this is helpful for someone!
777 - Tyler Dahl