How are your coffee beans lately? Mine are GREAT again!
So boiling in very weak vinegar and then Bicarb is done (about 2 tsp Bicarb to 10 litres). The vinegar didn't dislodge anything but the pot was nice and shiny after it. OTOH, the bicarb follow-up did dislodge some stuff - not a huge amount but certainly visible.
Just bought a fresh packet of Campos to get us through until the Silicia arrives, and I'm finally having the standard of coffee I have come to expect from this set up! It would seem that when crap beans are put through this Moka pot they leave a residual crap flavour which then takes a number of subsequent brews to get rid of.
Perhaps I need to boil the pot in Bicarb maybe once per month to freshen it up.