Hi All - Recently I bought a lightly used Savinelli and the it smelled sour and ashy. It had very little if any cake and I lightly scrapped and sanded the bowl and cleaned with isopropyl alcohol. Still smelled. So I sanded a little more and soaked with Jameson for several hours. To my delight she sweetened up nicely. It remains to be seen if she smokes sour and needs more cleaning but I am happy for now.
Next time a large grain salt and Everclear soak overnight (or I usually like to do a whole day) will do the trick without adding extra flavor - obviously you can substitute the Everclear with any high alc % drink of your liking.