I followed this tutorial successfully. Tried on 3 AirPods (from 2 pairs) and got two of them working again. Except for a little bit of soldering this is really no more difficult than replacing an iPhone battery. If you are on the fence, give it a try.

I found a very easy way to get the case off. Slice up a Pepsi can and cut out a couple of squares, 2" long by 1" wide, and round of the corners. Then once you have a spudger in, work a piece of the sheet metal into the opening, sliding it in behind the spudger as you work it along the gap. With this one weird trick I I had my ipod open in a couple of minutes without any damage to the case or the retaining clips.