Boycott beers sold in plastic rings, that goes for cider and shandy too. This can help to reduce the awful harm to wildlife they do. If you see any one the ground, just pick them up, rip up or cut every single hole, and bin securely. By law, they have to photo-degrade. But by law (just like balloons) it takes months before this happens.
Meanwhile, they get caught around wildlife (choking or strangulation or like this duck with a plastic ring stuck in its feathers). And when plastic ‘degrades’, it’s not the same as biodegradable. It just breaks down into millions of invisible plastic pieces, which do just as much harm. Peanut the turtle had her shell warp around the plastic rings she was caught in. Although rescued, she now has to spend her life in captivity, because her organs did not develop properly, poor little love.
You can recycle beer bottles at bottle banks (metal tops go in household recycling). Use a can crusher for easier recycling of lots of cans, and refuse plastic cups at football matches.
Report any plastic beer rings you see to Fix My Street. This site takes complaints with photos, and reports to local councils (who have a legal obligation to clear up on public land). Because the complaints are made public, things tend to be cleared up quickly, especially if many people report the same issue at the same time.
E6PR makes compostable edible six-pack rings for beer, made from wheat and barley (by-products of the brewing method). Currently this is expensive, but the more that people buy them, the sooner the price will be more affordable to all beer companies.