Video out of Hong Kong shows a protester turning tear gas into its harmless solid form.

The clip shows a demonstrator rendering a CS gas grenade useless by placing it inside a liquid nitrogen canister.

He then pours out the contents, which are solidified and therefore not a threat to protesters.

"This is what happens when you have chemistry grads fighting against tyranny," commented Ian Miles Cheong.

"Imagine what they could do if they had degrees in Sociology and Gender Studies!" joked another respondent.

As we previously highlighted, with the protests showing no signs of slowing down, authorities in Hong Kong are now considering imposing martial law.

Chinese troops are also massing on the border, although most experts say they won't be sent into Hong Kong.