Hi Jinho,
The sandpaper came in sheets. I just cut the sheet to fit the entire inside and wrapped it around the inside of the canister.
I am having trouble posting the image. The nice thing about wrapping the sandpaper is that you don't have to glue it down. We were going to use a glue gun, but there was no need. I can PM you if you want the images. It really worked great, especially because it didn't change the diameter of the ball.