Koshering pots

When boiling and koshering pots  does the water have to boil over the sides of the pot? Or can we just bring the water to boil and spill it out? 

Koshering Oven and Stove

Hi Rabbi, When Koshering the oven/stove, you are not supposed to use it for 24 hours before koshering. Can you use the stove to boil water for koshering other utensils/use oven for kosher for passover food during the 24 hour period?