Throw water at flamers
I'm not interested in salt but as many of my recent games have shown me my teammates must be nursing a deficiency.
I've found the most effective solution is to complement them and offer them well wishes.
Flamer: You are so fucking bad you should just kill yourself. Me: I'm sorry that you are having a rough day. You are doing great! Try spending time with friends and loved ones to help make lite your situation. Best wishes. Flamer: (silence)
Important to not directly reference whatever has happened in the match when doing this because they will flip it somehow or see it as satire.