Great idea dweste. I have to try it.
Maybe I can help it by wrapping the mug in a towel.

All right. I will forget about the upside down iron.
Maybe an electric kettle plus dweste idea will solve the electric cookset issue for air travel.

Regarding car and bus travel
I have a few sternos but will hesitate to take them in a bus luggage. No one will check, but I don't feel comfortable as it may leak or worse ( in summer heat ). But I can still take it on camping trips in our cars.

I love the esbit concept (safer than liquid fuel) but good solid fuel isn't availabe. And I have little idea how practical it is for cooking. Has anyone here tried it ? Any positive or negative thoughts ?

The solid fuel available around me is sold as barbeque starter type. During use it produces a cloud of soot and leaves some residue . I don't feel it safe enough as a cooking fuel. But we use it to start the coals anyway.

I May have to order Esbit fuel online.

Wait an minute !

Has anyone tried merging an Esbit stove with coals ?

You put 2 or 3 coals in the Esbit stove, drop a tiny solid BBQ starter on them ( or a vaselene/cotton ball) . Start the fire, when it near dies, the coals have just started. Put the pot and start cooking. You may need a better wind screen in this case, but it may work.

Fuel is VERY safe for car or bus travel.
Anyone tried that ?