Why does the Torah mention the ear-rings?
Targum Yonasan, Sechel Tov: Because the people of Shechem painted the image of their gods on them.
Chizkuni, Oznayim la'Torah: It is referring to the earrings that adorned 1 the images.
Moshav Zekenim: Yaakov told them to switch their garments. Ear-rings are an adornment for women, so men may not wear them 2 (Devarim 22:5).
Ha'amek Davar: Yaakov requested only idolatry itself, which cannot be Batel after a Yisrael acquires it. They gave even what is used to serve or adorn idolatry, which can be Batel afterwards.
Shemos 32:2,3 implies that it was normal for boys and men to wear earrings! Perhaps it was normal only for the Erev Rav. However, if the only problem was "Simlas Ishah," why did they need to bury them? They could have given them to their mothers or sister(s), or saved them for their future wives or daughters, or to sell them! This requires investigation. (PF)
Avodah Zarah must be burned, or crumbled and thrown to the wind (Avodah Zarah 43b). Why did Yaakov bury the idols of Shechem?
Ramban, R. Bechayei #1: Because the people of Shechem had already nullified their gods (refer to 35:2:1:1), in which case the idols were basically permitted, and even burying them was merely a stringency. 1
Moshav Zekenim: If kings would pursue Yaakov's family, and say, "The people of Shechem accepted not to serve idolatry - why did you kill them?," they will be able to show them that they were not Mevatel their idols, 2 and similarly they did not fulfill their stipulation about Milah, rather, they regretted afterwards. If so, they properly killed them.
R. Bechayei #2: Yaakov could not delay to burn them (or take them to the Dead Sea), lest surrounding nations gather against him.
Why did he bury them specifically underneath an oak-tree?
Ramban: Because it was a location which would not be tilled or sown.
What are the ramifications of the fact that Yaakov buried the Avodah Zarah underneath the oak-tree in Shechem?
QUESTIONS ON RASHI
Rashi writes: "'Im Shechem' - [meaning] next to Shechem." Why not explain 'Im' as usual - 'with'?
Gur Aryeh: One cannot say 'A is with B' in this case, for that puts the two on the same plane. Here, the city is primary, and the tree is merely next to it.