In a pinch, you can use rolled / crumbled scraps of paper towels from the bathroom. It's quite common here (Berlin) and absolutely no one looks at you strangely

In a pinch, you can use rolled / crumbled scraps of paper towels from the bathroom. It's quite common here (Berlin) and absolutely no one looks at you strangely if you do that. Some good clubs only have the bass really loud but it's not as common as it should be. High frequencies are what causes ear damage.