Recall many many years ago when I was instructing an instrument student in his Cessna 182, at 2am on the ILS R25L at KLAX, he tosses his cookies, all over the panel.
Ugh, what a mess.
At the sight of this, I didn't feel too good either.
We landed and taxied to the CAL hangar and he cleaned up himself, and his aeroplane.
He told me then...'i'll never do that again, too tough to clean'.