'85 CRX Head Liner

I recently picked up very clean and well maintained '85 CRX, one owner,
always garaged with cover. Only 67,000 miles.

Although I'm very happy with it and it's condition, I have recently noticed
that the 'foam' head liner seems to have become rather tacky and easily
damage by just your fingernails when you reach to pull down the sun visor. I
doubt that is how it has always been, but suspect that it has come with 20
years of age. Since it had always been garaged, I doubt that it is result of
heat. The car has spent it's life here in the Pac. NW, I'm wondering if it
could be the high humidity.

Is there any remedy??

Thanks,

Steve