Other issues to watch out for when food, wax, etc. is attached to the part where there is no letters, numbers, etc.
Is One Allowed to Salt Vegetables When They Are Sliced or Peeled?;
A few more pointers on torn or crumpled pages.
What Should One Do If They Pressed a Button of the Bell, Watch, etc. by Mistake? Electric Water Meters on Shabbos. Winding Swings on...