Drug info - What fake powdered substance is used for Cocaine snorting scenes in Films?

[cocainefilm]

SWIM is looking to make an independent mock-documentary type film in the near future about cola usage and the effects of using the powdered substance. SWIM is looking to use close up shots of the actors snorting a fake cola powder substance. SWIM has been told by some of my film colleagues that we should perhaps use baby milk formula or perhaps just powdered milk.

Does SWIY know if this is correct, and if not what substance could be used to fake cola for film purposes

Thanks in advance