I know, I know. Many of you will read this and tell me to go figure it out or come up with something original. At the risk of that, let me state the case. I was given a packet trick some time ago without any description and put it away until this morning. It consists of a blank backer, two regular aces, and two aces with blanks backs. What on earth is this trick? I thought Trost, just because, but am not sure. Can anyone advise?

Could be Factory Misprints from JC Wagner

Factory Misprints has a blank facer rather than a blank backer. At least, as its described in "The Commercial Magic of J.C. Wagner"

That was based on a Peter Kane effect called Blank Amazement but not sure what those cards were.

I could be Peter Kane's "Blank Amazement." My set has the same 5 cards only in 7's instead of aces.

The effect: Four playing cards are shown to have regular backs and blank faces. The performer causes the cards to become printed instantly with a "four of a kind" all the same value, a club, a heart, a spade and a diamond.