Re: aeropress again?

Jack Denver wrote:

Having "something" in the cup is not as easy as it seems. If the "something"
is metallic you may get sparks. Otherwise (glass marbles) you have
something that can spill out and splash, that you have to keep track of,
etc. Much easier to just not overheat the water in the 1st place.

I wonder if this could be prevented simply
by having an unglazed spot on the cup, sort
of like a built-in boiling chip?
.