EA defat: Before making the alkaline paste, soak ground powder in EA and decant until EA color doesn't change significantly. Dry off EA. If powder clumps up grind again before starting normal process. Would be experimental, so issues could arise. On the other hand, a lot of junk would be removed.

Sending samples: I think it is pretty safe and have used it several times. But that is just my opinion. I don't think samples in the <.1g range inside a plain letter are an issue.