I found some and just used it last week. Amazing results .
Sorry I didn't realize this wasn't a PM. I was trying to get past ten post's so I could reply. I used a product called Aluminum Black & Brass Black, gunsmith's use it to refinish gun parts. They come in little blue bottles are essentially acids that oxidizes the metal.
Hey what did you use to weather the aluminum parts? I have tried various things but none have come out like yours.
