[Terr_]

I expect it's much easier to acquire fine sandpaper, yet my inner child yearns for laser decapping. (Or I suppose more than "decapping", depending on the depth.)

[jacquesm]

High power lasers are becoming more and more affordable. Laser ablation is definitely an option but you really want to have some proper fume extraction around that.

[BertoldVdb]

Laser decapping will destroy the die, except if you have a rare package that does not mix glass in the epoxy.

You could still compare the internal structure of the package and bonding, but the die itself is mostly destroyed.