Joanna,

I have used milk, and detected no after odor. However, we grow outside, so
it might not be as noticeable. Nevertheless, mild dish soap and water works
very well for me, as does alcohol. The milk seems to give the leaf a matte,
'finished' look. So, if I'm going to show a plant, I'll clean it up with
Ivory or alcohol and then give it a light rub with milk.

Diana