Understanding the Difference Between the Melacha of Kotzair-קוֹצֵר (Reaping) and Gozez-גּוֹזֵז (Shearing);
more examples of "מבטל כלי מהיכנו" (nullifying a vessel from its normal usage) that come up on Shabbos;
tearing off the strip of plastic on the sides of plastic containers