I think that was quite a dull tone and an unnecessary comment. If the TS wants to paint the beams in different pastel colors, then it's up to him, right?
Regarding the thread, I have seen a machine with a small rotating nylon brush. It was probably a patination machine, I think it was Jula or harald nyborg. If it works, who knows.
Steel brush on the angle grinder or "rasp disc" for the angle grinder. I used these in combination to remove pastel colors from the beams in the kitchen, but my beams are much smoother to begin with.