Sefer torah
The ink
the ink used to write a sefer torah may not have any other ingredients than what is needed to make the ink, so one may not put in the ink fly spray.[1]
the ink is made of oils, nuts and gums into a paste which will be the ink for the sefer torah
The parchment (klaf)
the klaf parchment, is made of a kosher animals hair, processed and smoothed and refined into parchment.
one mistake?
even if in one letter in one breishis (or shemos or vayikra or bamidbar or devarim) in one parsha in one aliyah in one perek in one passuk is faded even a tiny bit or scratched or rubbed out a little the whole entire letter and perek and aliyah and parsha and sefer and the whole sefer torah is pasul
there is one exeption. in parshas pinchas perek 1 passuk 3 the last letter: shalom, the vav in the word shalom is cracked but it is not pasul the gemara[2] says that without the letter vav, the word reads shalem: “unblemished” or “whole.” Thus the verse alludes to the law that kohanim who serve in the beis hamikdash must be physically whole.
