I have some damaged-beyond-repair self inflating sleeping pads. On one the hard gel housing the valve has completely disintegrated so it cannot be inflated at all.
Two others have dozens of tiny holes, courtesy of the cats’ claws. While I started patching the holes with blobs of silicone gel, I gave up as there seemed to be just too many. They can be fully inflated but slowly deflate after a couple of hours. I’ve used the ¾ size one as a “lunch pad” on day hikes but it seems a bit overkill for such brief usage.
How have you successfully repurposed your old self inflating sleeping mats?