Avodah Zara 76: Kashering Used Vessels

This last daf of Masechet Avodah Zara begins by concluding the rabbis' discussion regarding kashering vessels that belonged to Gentiles.  The rabbis suggest that the longer that a liquid is held in a vessel, the more that it is absorbed into the vessel.

The Gemara moves on, wondering whether a Gentile's roasting spit can be kashered using immersion in hot water.  Do holy vessels absorb more permitted tastes?  Or more forbidden tastes?  Must they be rinsed and scoured?  How long does the smell of past  foods last?  Do those vessels emit past aromas?

We then learn about methods of kashering.  These method are still used today:

• Rav Mani: heat until the surface peels off
• a small pot is kashered by being place in a larger pot in boiling water
• a large pot is filled with water and boiled
• Drops might splash onto the top of the brim
• a knife is kashered by rubbing it on a sharpening stone
• A knife can also be kashered by put in and out of the ground ten times
• A knife without crevices can be kashered in this way
• if the knife has crevices, it must be kashered in this way
• when a knife is inserted into the ground for kashering, it must be otherwise unused 

Our daf ends noting that slaves were offered to Bati and and Yehuda.  One accepted this 'gift' and the other did not.