How to clean a cauldron

A unique technique for cleaning is from very old carbon ... or how to kill time on the day off. The elapsed time for cleaning is 2.5 hours. The result, as for me, is worth it. The procedure at the very beginning, of course, can be skipped, but it will be boring. I tried to get rid of the effects of alkaline oxidation of aluminum at the end - I cleaned everything possible and at the end polished it with a soft cloth. The whole process would be more likely to be attributed to humor than to the manual for cleaning dishes ... although it may be useful to anyone.