PathWalker
I use my vintage decks, but I can't riffle shuffle anyway
What I often do is deal the deck out into piles, sometimes 7 piles but I'm not worried about the numer. But doing that mixes them in a different way. Then I overhand shuffle. Then I feel the cards have had a good mix up. If I have no space for that I might move them '1 card to the front of the pile, 1 card to the back' all the way through the pack, then overhand shuffle.
Anything that changes the way they were, and makes them feel better mixed.
But ultimately, they belong to you, you can do whatever you want with them. And if you couldn't bear to be without a deck like that, make sure you have a back up.
Enjoy
Pathwalker
What I often do is deal the deck out into piles, sometimes 7 piles but I'm not worried about the numer. But doing that mixes them in a different way. Then I overhand shuffle. Then I feel the cards have had a good mix up. If I have no space for that I might move them '1 card to the front of the pile, 1 card to the back' all the way through the pack, then overhand shuffle.
Anything that changes the way they were, and makes them feel better mixed.
But ultimately, they belong to you, you can do whatever you want with them. And if you couldn't bear to be without a deck like that, make sure you have a back up.
Enjoy
Pathwalker