Fingerprints; invisible ink; writing on one skin; x-rays.
Is One Allowed to Trap an Animal That Is Sleeping, Blind, Lame, Old, etc.?;
How to Handle the Melacha of Borer Regarding Leftover Feathers on Cooked Chicken;
could we say that "קיימא (permanence) applies to תופר in conjunction with gluing, taping, sticking, etc.