Generally medical professionals do not vouch for using milk for tear gas despite it often being touted. The research seems to suggest they are largely the same in providing relief
Sources to back this up
That means bacteria can contaminate the milk and potentially cause infection if applied to eyes or skin wounds. Jordt says it’s better to use water or saline solutions to wash out eyes after a tear-gas attack
Another source of medical professionals recommending against it
And a study looking at pepper spray as well
In this study, there was no significant difference in pain relief provided by five different treatment regimens. [Water vs milk vs 3 other solutions] Time after exposure appeared to be the best predictor for decrease in pain.
That only counts for OC gas (pepper spray) - most anti-dissent chemical weaponry doesn’t contain capsaicin. Milk won’t do shit for CS gas, for instance. For CS gas, water is the only thing that works.
Considering how many different types of this shit there actually is and the fact that they can mix them up pretty easily regardless of what the law actually says makes a one-size-fits-all solution pretty difficult.
edit: did I just say a one-size-fits-all solution to this is difficult? Silly me.
Science Direct website says that