Avodah Zarah, Daf Nun Gimmel, Part 1
מתני׳ כיצד מבטלה קטע ראש אזנה ראש חוטמה ראש אצבעה פחסה אע"פ שלא חיסרה ביטלה
How does he annul it?
If he cut off the tip of its ear, the tip of its nose, or the tip of its finger; or if he defaced it, although there was no reduction in the mass of the material, he has annulled it.
In order to annul an idol, the idolater must treat the idol with enough disrespect that we can be confident that the idol is no longer considered to be holy by the non-Jew. Note, that the issue is not a physical issue. The mishnah is not asking the question, does this still look like an idol. Rather the issue is psychological. At what point can an outside observer assume that the owner of the idol no longer is relating to it as a god, but rather as merely a physical item devoid of religious meaning.
The first way for the owner to annul the idol is to somehow physically damage it. If he cuts off one of its appendages, this is sufficient physical damage for it to be annulled. Furthermore, if he defaces, meaning he distorts the facial features of the idol, it is annulled, even if he has not diminished the material used to make the idol.
רק בפניה השתין בפניה גררה זרק בה את הצואה הרי זו אינה בטילה
If he spat before it, urinated before it, dragged it [in the dust] or hurled excrement at it, behold it is not annulled.
Acting in a disgraceful way in front of the idol does not annul it.
מכרה או משכנה רבי אומר ביטל וחכ"א לא ביטל:
If he sold or gave it as a pledge, Rabbi says that he has annulled it,
1) but the sages say that he has not annulled it.
If a non-Jew sells or uses the idol as a pledge, according to Rabbi [Judah the Prince] he has annulled the idol. Since he treated it in a profane matter, and did something that one would not do to a divine idol, he must no longer be considering it to be an idol. The other Sages disagree with Rabbi.
גמ׳ כי לא חיסרה במאי ביטלה? א"ר זירא שפחסה בפניה
GEMARA. Since he did not reduce the material, how could it be annulled?
R. Zera said: Because he defaced its appearance.
As I basically explained above, since he defaced the idol it is annulled, even though he didn t actually break anything off of it.
רקק בפניה והשתין בפניה מנה"מ אמר חזקיה דאמר קרא (ישעיהו ח, כא) והיה כי ירעב והתקצף וקלל במלכו ובאלהיו ופנה למעלה וכתיב בתריה ואל ארץ יביט והנה צרה וחשכה וגו’ דאע"ג דקלל מלכו ואלהיו ופנה למעלה אל ארץ יביט:
If he spat before it, urinated before it From where is this rule derived? Hezekiah said: Because the verse stated, And it shall come to pass that, when he shall be hungry, he shall fret, and curse his king and his god, and turn his face upward, and following this it is written, And he shall look to the earth, and behold distress and darkness (Isaiah 8:21). Thus, although he cursed his king and his god and turn upward [to the true God], he still looks down to the earth.
The verse here describes an idolater who curses his king and god, and then looks upward to the true God. Nevertheless, he immediately looks down to the earth, which Hezekiah reads as continuing his idolatry. Thus even though the idolater shows his anger at his idol, he has not really annulled it, even if he spits or urinates on it.
