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.
I got pepper sprayed in the military. In order to be allowed to wear pepper spray on our belts (for law enforcement), we had to be pepper sprayed and fight someone off.
I found it strange, because it’s not like we had to know what it was like to be shot and fight back. It was also one of the worst experiences of my life. Getting accidentally splashed across the eyes with hot sauce ended up not so bad simply by comparison, so I had that going for me.