Any advice on reversing curvature on 1980s 3D cards?

[andy]

They look a tad humpback.

 

[wdkantro2]

No idea, but what I did with 2001 bowman chrome baseball that were curved is put them in a toploader and put a book or something on top.

 

[andy]

Right now I have them ducktaped between 2 of those snaptite holders.

:cheers: OMG a good use for snaptites!!!