-in liquid nitrogen canisters.<p>vacuum flask; Dewar flask or ^Themos^ bottles
all apparently similar items.<p><a href="https://en.wikipedia.org/wiki/Vacuum_flask" rel="nofollow">https://en.wikipedia.org/wiki/Vacuum_flask</a><p>The truncated title gave me the impression the burning CS canisters were being thrown into liq nitrogen !
im sure that would be spectacular.
anyway, i think any old empty paint can might do it if the grenade extinguished before the gas pressure blows the lid off, but it doesnt hurt to be a little exessive when its critical to contain.