What on earth is this?

[JulianCat]

I'm in the process of changing the wax ring at the bottom of the toilet.
I'm going for one of the cool Sani Seal green rings.
The toilet is very old, but still works find.
I had it upside down outside and was shaking the bottom of it to drain water from the bowl, and this black rubber thing fell out. Maybe it has nothing to do with a toilet and I'm better off without it. Maybe it's some critical part and without it the toilet won't function. But I wasn't able to find where it should go.

Any thoughts? Can you help solve this mystery?

Thanks you so much!
-Julian

 

[CountryBumkin]

Could that be a toilet lid/seat fastener? Is the center part threaded?
Looks like you could insert it into the seat "bolt hole" in the porcelain bowl then insert the seat bolt and tightening the bolt to compress the rubber which holds everything in place.
Or maybe not...

 

[Sponsor]

 

[Reach4]

There can be holes needed by the molding process. These can be filled with different materials. The hole could be filled with ceramic material by a craftsman before firing. That would be done if the hole area is visible in use. Could be plugged with elastomer after firing and glazing. Maybe that rubber plug was filling such a hole.

If the toilet needs plunging now and then, you might consider putting in a new toilet the next time you lift the toilet.

 

[JulianCat]

> you might consider putting in a new toilet the next time you lift the toilet.
That's exactly what I did. The toilet was from the 1930's I think. A new one didn't cost much.
So the answer doesn't matter anymore. Thanks so much for your advice CountryBumkin and Reach4!