Cheap freight options for Dangerous Goods in small quantities

[Mr Griffin...]

Hey,

A friend at uni wants to send small samples of Hazardous goods (ca. 20mL of Class 3 Flammable liquids, and that sort of thing) to other universities interstate, for comparing results. What is a good, cheap & legal option for the postage of small amounts of hazardous goods?

Protocol for Packaging Groups and precautionary Dangerous Goods labelling will of course be strictly adhered to.

Thanks in advance for any advice.