Compact Mac carry bag restoration

[patters]

I was lucky enough to get one of the official carry bags with my Macintosh SE/30 but it's got some sort of material rot problem where it's shedding black powder on anything I put inside.

It has a tear at one of the seams and through this I can see that the main white foam padding layer is fine. At first I had guessed this main foam layer was the problem but it definitely is not. It's made of a bubbled polyethylene material like a camping bedding mat, which seems to have withstood the last 40 years absolutely fine.

What seems to have denatured is some sort of elasthane directly within the weave of the inner lining fabric. So... has anyone here restored one of these bags? Would I possibly get away with strongly vacuuming this lining, on the basis that this problem material has already perished and will just be disintegrated and removed by the vacuuming? Or will it keep on coming?

I could only find a single mention of this disintegration to powder online.

 

[patters]

Some cleaning tips I could find here:
https://www.reddit.com/r/VintageApple/comments/1ij229o
A mention of disintegrating fabric:
https://www.reddit.com/r/VintageApple/comments/9fu6mw

 

[patters]

ChatGPT suggests, based on my description, that it's likely a polyurethane (PU) coating on that lining fabric which has hydrolized. May have served as a moisture barrier. It's not too optimistic of a simple cleanup, rather suggesting replacement of the lining. That would be pretty tricky since it has the keyboard pouch part integrated (with its own foam formers).

 

[patters]

Some detailed pics, showing the disintegrated material (the light grey bloom on everything), particularly evident in the pouch in the top lid.

I think this will have to be entirely remade with a new liner. And I guess I will be sticking with cotton