Update -or- just Some More Bits and Pieces of Information.
Well, after I started this section of the exp, I found a video piece by Douglas McLaren of Cortez Pearls about Cleopatra's pearl-in-wine exploit. Vastly entertaining and informative and much more scientific than my report, in it he popped pearls into various solvents (like wine) and documented what happened.
I wanted to shout "No, Wait! Stop!!" when he started sacrificing the pearls; it hurt to watch that - A LOT, Douglas. I hope we don't see aaaaany - more of that out of you, young man!
Still, the experimentalist in me watched with horrified fascination as the pearls melted and bubbled. (Were they screaming like the Wicked Witch of the West in Wizard of Oz - I'm melting, I'm melting... You might be thinking She's nuts, she's nuts...)
I was impressed with the speed and thoroughness of the chlorine bleach, so I thought this time, I'd get bold and use straight bleach rather than diluted, as I had already. I figured I'd watch it closely and just do it for a very short period of time.
Again, no before photo. One day I will get a camera.
and, Oh, yes, I got distracted. Some 6-8 hours later I remembered that pearl and dashed in to see if anything was left. There was, although the size was significantly reduced, so crowing with delight, I scooped it out of the bleach and rinsed it forthwith, then soaked it for a while in two Brita Baths, then let it dry for a couple of hours. Don't you just hate the scientific inexactitude of my exploits? I'll do it seriously next time.
After a couple of hours its appearance was much like the pearl I'd immersed in diluted bleach after wiping w vinegar, sans color, with shiny and dull spots in patches all over it. I picked it up and rubbed at the dull spots and they didn't polish off with a cloth as they had on the diluted-cl-solution pearl, so I picked up a utility knife to gently scrape them off.
Darned if the dull spots didn't seem endless, so I exerted a little more pressure with the blade. Ladies and Gents, that nacre sliced off like cold butter, in smooth-sided slabs. I kid you not.
I laid down the utility knife disconsolately. What now? I remembered Barbie Biggs remark about keeping solvents out of the drill holes. So right, Barbie.
I soaked the pearl again in a Brita water-bath, let it dry and then a couple of months later, remembered it. It had hardened again, and I was able to gently shave off succeeding layers of nacre until I got to solid ground, so to speak, a more resistant-to-scraping layer. Then I rubbed it with a soft smooth cloth, and forgot it again, for a long time.
Well, it's a hard pearl again. There's a soft pearly shine to all areas when you turn it, but an uneven, wavery-look at rest. The surface is very smooth. The shape is rather baroque-round. Yes, the dye is gone.
The above-reported method is not the way to go. I'll try again under more controlled circumstances, because I still want speedy removal of dye.