"Ohhh...no no!", said the moto-taxidriver as I handed him a US dollar. He had noticed that the top right-hand corner of the note was ever-so slightly brown and burnt.
Oh no exactly. How did I not notice that someone had already slipped me the 'dirty' dollar.
Cambodian lesson #1 - always check that any change you receive in US dollars is in pristine condition. A dirty, torn or burnt-cornered US note is unacceptable.
However, as shown, Cambodian Riel - the local currency - is accepted in any state whatsoever!