Stefan,
as you know, I handle the dirt on carrots and the like
exactly like you.
Regarding Tamarillos: Did you know that they smell like
barbecue (for me) when they are ripe and that they get
lighter, not darker, when they get ripe?
That smell is very attractive and I normally bite into
the skin to open it but I don't eat it. This is simple
with ripe Tamarillos because the skin can then be
separated easily from the flesh.
-Karl