Dropped my necklace charm down overflow drain on bathroom sink this morning. No water was running. How can I get it out?

I don't know how that could happen, but if it did, you have to remove the drain assembly from the bottom of the sink and fish it out of the overflow passage.

How do I do that?

Take the drain to the wall apart, then "unscrew" the part that is in the sink. It is easy to SAY that, but seldom easy to do it. In fact, sometimes you have to saw it apart and install a new one after you are done.

And, whatever you do, Don't go outside in a thunderstorm today. In fact, if I was you, I'd go back to bed.

Did it go down the sink overflow hole, or just down the drain ?

you could try a shop vac held securely over the hole. usually, due to the nature of a sink overflow, soap scum accumulates in there and may have stopped the piece from going down too far..

There is a very good chance that its sitting in the bottom of the P-Trap. Remove the trap and see. If you can't remove it, ask a neighbor with the right wrenches.....

Best Wishes

If it really went down the overflow of the sink, which I cannot imagine how that could happen unless she "shoved" it in, it NEVER went through the overflow opening in the drain plug so it is still inside the sink.

most of the time, the openings in the drain plug are almost filled with the excess plumbers putty.

Also, it would be a rarity for the openings in the drain plug to line up with the overflow passage, AND, there is more "gunk" in the openings than plumber's putty.

so, in summation, there is a better chance of aaron hernandez going free than the jewelry washing into the piping below..

Exactly, And, since sink overflows are on the vertical portion of the sink it should NOT have been able to "fall down it", unless it was pushed into the opening.