The glue holding the bass damper felts on my Milton Player Piano had degraded to the point that the felts were falling off on their own. They were still in good enough shape, so I decided to pull the remaining felts off and re-glue all of them.
I start by holding the damper head firmly with one hand, while rotating the damper felt with the other until it comes free. I work my way along until all of the old damper felts have been removed.
If I were re-gluing the treble damper felts, I would keep them in order, but for these bass felts it doesn't matter if they get mixed up. Just keep the single-string dampers with the single-string notes and the doubles with the doubles.
To reattach the felts, I use Titebond Liquid Hide Glue. Since the damper springs will provide the clamping action to hold the felts and damper heads together, I don't need the quick set that hot hide glue offers. The liquid hide glue is much easier to work with and requires less set up time as well as less clean up.
Some of the damper felts are not horizontally symettrical, so make sure that you keep them in the same orientation as they originally were. The easiest way to do this is to keep the dirty side of the felt up and the clean side down.
Apply a small amount of glue to the back of the damper felt and then, using the strings as a guide, slide the damper down behind the corresponding damper head. Allow the spring-loaded damper head to clamp the felt against the strings.
Try not to apply too much glue as it will squeeze out and fall onto other parts of the action where it doesn't belong.
Keep working along from left to right. Going this direction will allow you more working room as well as better vision of the glue joint.