After cleaning and buffing the lugs, dropouts, bottom bracket shell and fork crown with Belgom Alu, these parts are nice and shiny. Perhaps I could have mirror polished them with # 4000 sandpaper, buffing wheel and elbow grease, but I'm satisfied with the current state.
I filled the "cut-outs" of the lugs and the "ALAN" logo's in the fork crown with glos black enamel paint. You'll get a perfect result if you use Revell Email color and a small brush. The triangle cut-outs can be filled easily. Pantographed parts seem to be a bit harder, but that's even simpler. Just paint the part roughly, with enough paint in the letters/figures and don't worry if paint is spilled on the surfaces that have to remain unpainted. When the painting is done, whipe the excess paint off with a thin cloth. It's an option to let the paint dry for approx. 15 min, but then you have to whipe the excess paint off with some white-spirit.