As promised, some pictures: dried up residue in the scale and the residue when scraped together. This is residue of 7,5g MHRB soaked in grain alcohol.

I redissolved the residue in approx. 5ml vinegar and 45ml water in a shot bottle (for its verticality) to try out the freeze/thaw experiment mentioned above. Will update on the results when done.

Strangely, there were instant formations of dark clumps. I tried to separate and mix them in with a pointy knife but this was difficult because they were very sticky, like one of those boogers that keeps sticking to the finger you try to flick it away with. They have since mostly dissolved, however.