And....after you have rubbed all the old foam you can off the board --- do a good spray coat of adhesive and let it dry. Then spray it again. I used what the manufacturer recommended on mine but it was not enough. Had a place in the back where it came undone. You don't want that to happen after all the work of re-doing it. The extra $15 for another can is well worth it.
The condition of the foam probably has a lot to do with it. If it has deteriorated into oily goo, it will make it very difficult for any adhesive to do a good job.