How do you cleanse Tarot Cards ?!

Hey beautiful people!

I sort of inherited my grandmother and great aunt's tarot decks and I keep them outside my room, I don't touch them (because I've read you should never touch other people's decks without express permission), I hardly even look at them ! 😅

My question is, how do I responsibly and efficiently change the decks'ownerships to me ? Is this even possible now that they're dead ?

Maybe can I just cleanse them of their previous energy just to be able to hold the cards and look through them and study them (they're very old decks) but not to use myself ?

My grandmother was a very nasty woman, and she was suspicious of everyone and very possessive and secretive, so I don't want to tread where I shouldn't. I never met her sister, but I imagine she was a normal lady.

Thank you for any and all help!

~ Blessed Be ~