The roving mobs during the DNC 2000 in Los Angeles absorbed pepper spray showers relatively well, the pepper balls shot by police were rather effective shooting out a CNN camera live on television (standing in the zone that police instructed all press to gather in not five minutes before they started shooting that zone.)
This was in response to a plastic bottle hitting Billy's car which they parked in front of the mob (on the other side of a 12 foot fence.)