re: In movies when they snort cocaine............

If they have a decent Propmaster, they snort Inositol.

Inositol is a water soluble B vitamin (B8), and is also known as a lipotropic factor and is found in both plant and animal tissues.

It is kind of sweet tasting when snorted up the nose and does not burn or clog the sinuses.

Some guys use lactose powder which is a milk sugar, but that clogs the sinuses and can lead to inflammation and general yuckiness in the nose and sinus cavities.