R' Yishmael says: Three matters are among the lenient [decisions] of Beis Shammai and the stringent [decisions] of Beis Hillel. Koheles does not render one's hands tamei, in accord- ance with the words of Beis Shammai. But Beis Hillel say: [Koheles] does render one's hands tamei. The purification waters that have accomplished their purpose: Beis Shammai declare [them] tahor. But Beis Hillel declare them tamei. Ketzach: Beis Shammai declare it tahor. But Beis Hillel declare it tamei. And similarly, [with respect] to tithing.