As you may remember (or just plain don't care) from a while ago I was trying to get the right finish on my cam cover to match the rest of my motor on the 39 EL I'm building. I tried a lot of various tricks people recommended (see previous post on the subject). Everything from a battery acid, drain oil, coca cola mix to gasoline to a brass brush, salt, on and on. Thanks to all for the recommendations.
Here is what worked for me:
I had recalled that sand blasting aluminum gave it a dry, grey, dull, semi rough finish...hhhmmm...kinda what I was looking for...
I taped up the inside of the cam cover and covered the holes with duct tape, I bought a bag of play sand from Home Depot and lightly blasted it until it was the texture and color I wanted, I them rubbed it with old "mung" fromunda the trans on my other crusty 39 EL (I keep some in a jar for just such an occasion). I cleaned it off with a dirty rag and rubbed in some more until it seemed right (to me). It came out pretty good and I can give it further treatments once the bike is all together.