you are not "extracting" cash, you are claiming free giveaways that happened a long time ago. some of them are timed out since they are too old and some still work. if there was a fork that copied the whole blockchain of a cryptocurrency and created a new one and you had a balance prior to that copy/fork then you have the same coins in the forked chain.
you should beware of the risks of claiming these coins though, not just replay attacks but also infecting your computer by having to install shady wallets.
also take a look at this site:
http://www.findmycoins.ninja/I love how that site is .ninja. Yes it is not really extracting, it's like clones of the existing coins inside wallets before the forks happened, that is exactly what it is. Of course it rewards the innovations/founders a lot more and they rightfully deserve it.
It's
really important that you are aware of the risks involved while claiming them. Where there's money, mostly always someone will attempt to scam you, sadly too much not so innocent people in this world.