Here I will show the results of cleaning the burning on the wing and processing the cleaned surface with a rust converter. Cleaned with a hard cord brush "bowl". Soft soot did not peel off.
Photos are a bit blurry due to low lighting.
Inner surface
So, what happened before the purge.
After cleaning and a single treatment with a rust converter.
Rust converter treatment was carried out on a vertical surface (the wing was on the floor), hence the black smudges. This is how the acid drains, taking loosened particles of rust with it. Well, since the technology says that after processing the part must be left alone until completely dry, all this "muck" was deposited along the way, and immediately dried up. In principle, all this is easily cleaned off (this is also mentioned in the instructions). Even the rust that was sitting very firmly, and which the cord brush did not take, is cleaned off. So, after several treatments with a rust converter and mechanical cleaning, everything was cleaned off, and the surface acquired a gray color, that is, it was covered with zinc. By the way, each time I cleaned the dried surface not with a hard, but with a soft cord brush, so as not to clean off the zinc layer. The operation was repeated three or four times.
In the end, this is what happened:
Outside surface
That's all. Until next articles.