glue and dust

@Marie-Hélène Ammor: This is from a steel cylinder where posters are glued for publicity. This is the original colour, some greenish colour can be detected in the upper left corner.

@QUIM: You gave me the idea.

@vu@granby - Wolfgang: I'm stunned. This is perfect Portuguese. When you say "obrigado muito" (merci beaucoup, thanks a lot) is in reverse order. We say "muito obrigado" (beaucoup merci, a lot thanks).
Btw, thanks for the comment.