Boy, this is a toughie. I'm shooting some mil surp that is a flake powder, that if it were mixed in with anything Alliants "Dot" series or Unique, I doubt I would be able to tell it by a simple visual examination. I'd be hard pressed to tell if the Green Dot had been mixed with Unique. A toughie for sure, I used to burn a lot of Green Dot in 45 Colt and 45 ACP, a good powder. For me, the question would boil down to how well you know and trust your friend. About 2 years ago I was using some 5744, and was going to change out to Reloder 15. Well, I did the goof and dumped the 5744 from my measure into the R-15 jug. I poured the powder out onto a newspaper, couldn't tell noe difference.....I scattered it in the woods.