The plastic measuring spoons have triboelectric properties that repulse the JJ powder, launching small pieces all over the bench. It always makes a bit of a mess.
Recognizing this, I bought myself a nice stainless steel measuring spoon, which has no such issues.
This was a bit hard to find in a suitable shape along with the correct volume, and it wasn’t really cheap. Maybe you would consider offering such a stainless steel measuring spoon, either to replace the plastic one, or as a “paid” alternative?