The most credible routine I use is as follows:
"Bought this deck of cards... was fine at first. But the more and more tricks I did, the ink rubbed off... except for the Jokers <TWO JOKERS FROM A MATCHING REGULAR DECK ARE ON THE FACE - THE MAGI REMOVES THEM>
This wasn't a problem - as we know that not everything lasts forever. I noticed the guarantee printed on the Joker card... see?
So, I phoned up the Bicycle playing card company in the States, the people who make the cards.
The guy said 'no problem - send one of the defective cards along with proof of purchase, and we'll look into it'
I paused. I asked him 'Well, there's nothing to see. They're all blank. You'll just call me a nutcase'.
'on the contrary!' he retaliated...
'... Our cards all contain a unique ink - which can be revitalised, if you know how. We'll just check if your card is a genuine card, then if you send us the whole deck back, we'll revitalise the ink, and send them back to you.'
Revitalise? Who's he trying to kid. So, I asked:
'So, it's going to cost me £5 to post the 'sample' to you, then another £5 for me to post the rest of the deck - UK to US airmail, we're talking at least three weeks. Why don't I just buy a new deck!'
The guy paused, and finally buckled...
'Can you keep a secret?' he said.
Me? A secret? Heh heh heh...
'Yes, why?'
'If I tell you how to do it, you promise you'll not tell anyone - my job's on the line'
So, after guessing maybe the guy WASN'T a fruitcake, I listened.
'Right. It takes a bit of concentration... As you cut the deck, think of a card - but concentrate on it's face...'
I thought he'd gone insane. But I humoured him...
'What, you mean - like if I concentrate on, say - the four of hearts???'
<CUT THE DECK - SIGHT THE CARD AND SAY THE NAME OF THE CARD AS YOU OPEN THE CUT. THIS GIVES A VERY STRONG ILLUSION THAT THE CARD YOU NAME (SEEMINGLY AT RANDOM) HAS JUST 'APPEARED'. CLOSE THE CUT (PUT THE TOP HALF UNDERNEATH - BEING CAREFUL TO KILL THE VIEW OF THE REAL BACK WHICH HAS BEEN REVEALED.
SHOW THE FACE CARD'S BACK - IT'S BLANK - PLACE THE DECK ON THE TABLE - KEEPING THE FACE CARD IN YOUR HAND>
My shock was evident as a four second pause, then I said:
'Crikey, that's unreal. But there's no back on it. I remember thinking of a back as well...'
'Ahhh...' he replied - 'Common mistake - it's probably on the back of the DECK...
<PICK UP THE TABLED DECK AND TURN IT OVER... YEP, SURE ENOUGH - THERE'S THE BACK. REMOVE IT, SHOW IT TO BE BLANK ON THE FACE, AND TABLE THE DECK - WITH THE SIDE YOU'VE JUST TAKEN THE BACK CARD FROM UPPERMOST>
'You're right. I'm amazed. But there's no face on it.' I said.
'Figures. Now look through the 52 blank cards you've got, and try and imagine the whole deck. This is the hard part... that's why we use meditation here - it's much quicker - we can do 20 decks per-hour'
<PLACE THE BACK CARD BACK ON THE DECK, BACK IS UPPERMOST. PLACE THE FACE CARD FACE-DOWN, SO THE FACE IS OPPOSITE THE BACK. THE TOP OF THE PILE IS BLANK NOW>
'So, look through the deck <RIFFLE, OR EVEN BETTER, CASCADE THE CARDS TO SHOW BLANKS ALL ROUND> and imagine every card in the deck.'
'Yep, that's all there is to it. Don't forget to imagine the 52 backs as well. And be careful with Aces - they're tricky. Just cut the deck and imagine...'
So I did. And amazingly, there, in front of my eyes, were all 52 cards, fronts and backs <YOU KNOW WHAT TO DO HERE

I HOPE!!!>
'But one word of warning!' he said, as a final note...
'Oh, I knew there'd be a catch...!' I replied.
'Just remember, if at any point during the performance you break concentration, the cards will vanish.' - the bombshell came.
And he was absolutely right - all the cards were once again blank. And so I kept the deck <PUT IT BACK IN THE CASE AFTER SHOWING THE BLANKS AGAIN> not only as a reminder, but it makes a pretty good trick, too, don't you think???