Is Swap Space being cleared automatically? If yes at which step?

Hi Folks,

this is probably a quiet basic question, but I am currently unsure about it.

When pages which were swapped out to swap space, are being swapped back in because they are needed in RAM, are the pages cleared from the swap space?
Or will we have the information twice, once in swap space and once in RAM?

Another question,
When a process which has pages related to it currently residing on swap space, is normally terminated,
does the pages in swap space get cleaned/cleared or does the info reside in swap space until it gets overwritten?

Appreciating any infos!
Thanks a lot in advance!!