I did try that once on my shadow masters with a porper clip but it wasn't tight enough.. I placed it partially inside and used my hands to squeeze the sides. but the problem with this is that the spread of ink isn't equal.. i may be bright on one end and darker at the other, might be my marker though. Using something to press the cards would be hard cos of the smooth finishes unless you could hold them together with a box of some kind. Oh, I forgotten to add a small detail, I used my lid-torn-off Aladdin 1001 tuck box to hold the cards in place but there's a small little gap for it to shake about so its really hard using this compress-cards-and-colour method.
But I was actually discussing pressing a SINGLE card at a time. Inking cards en masse never turns out good and they stick together when the ink dries. But if he was able to press a single card while having access to the edges, the compression could possibly prevent excess ink absorption and ruining the card edge. Wiping off the excess ink would help here as well.
I then though that pressing a card so you can access at least two edges would work as well, but would take twice as long.
But hey, we're just batting around crazy ideas... It's not like it's impossible to find a silver-edged deck, as long as you don't mind either cheesy bridge cards or expensive De'vo's Blades Blood Metal Edition. Or a vintage deck.