[jchcollins]

I will say that depending on the card thickness and holder manufacturer, I have had limited success in the case of something like a one-screw with putting a card that rattled around into a penny sleeve, and then getting it into the case in the recessed area a la a Beckett slab, and then the card no longer moves. The standard issue thin / glossy penny sleeve is a lot cleaner in most cases than the thicker one that Beckett uses. And those do come in pre-1957 sizes.