AirPods 2 main speaker volume low

So, these AirPods are old. I tried to clean them, and I noticed that the volume was low, and so I had to use the other AirPod. They are updated to the latest 6F21 version. The warranty is EXPIRED, so Apple can’t really do much. Now, after I tried to clean the other AirPod, I noticed that its volume was low. Has anyone else had this issue, and is there anything that can fix it?