It should work but i never tried it or read about it so maybe there could be a problem i can't think of
Here are just some thoughts that came to my mind
The HCl is volatile so it's perfect leaving no residue
I think the harmalas will be hard to scrape
The only real problem i'm aware of is that unwanted substances and impurities will still be there if no manske was done before
Good luck
"Is this the end of our adventure? Nothing has an end. We came in search of the secret of immortality, to be like gods, and here we are... mortals, more human than ever. If we have not obtained immortality, at least we have obtained reality. We began in a fairytale and we came to life! But is this life reality? We are images, dreams, photographs. We must not stay here! Prisoners! We shall break the illusion. This is Maya. Goodbye to the holy mountain. Real life awaits us." ~ Alejandro Jodorowsky