Some sibling comments mentioned replacing the rubber seal fixes the issue of burnt taste. I took a look at my rubber seals and they did have a burnt smell, so I'm gonna give that a shot. Thanks for sharing and good luck with your friend's Moka pot!
There's no more Moka pot; now he's on his own. ;-) I'm really surprised that my friend managed to melt the goddamned metal. I was wondering did the metal really melt? How long did he leave it on fire for the metal to melt? The bugger didn't answer these questions.
i think he obviously just melted the plastic handle, you just can't melt aluminium (let alone steel) with even a gas stove's burner.