Cutting the inside skin off. A hand grinders is a DIY essential; this only took a few minutes. Do wear goggles over your glasses, gloves and footwear; these are more dangerous than they appear. Yes, a wheel gaurd would help, but they constantly in the way.
We had noticed that the cover was spongy and heavier than it should be. I had also notice that when open it weeped water. It seems they had scimpped on resin when the laid it up, leaving pin holes all over. Since the locker is constantly wet, due to the drainage design, the core was constantly exposed to water vapor from the underside.
Not very water tight. Those are holes.
Removing the inner skin was a simple matter of grabbing one corner and pulling...
To releveal this....
And so I set about removing all that I could with a drywall knife and hammer. In fact, some of the core was left, since it could not be removed without damaging top skin. I treated what remained with a borax anti-rot formulation and left it in the sun to dry. It's interesting how the sections with enough resin were often fine, protected by resin in the cuts between the blocks. Right next to a good cell was mush.
I'll give it ~ 3 days in the sun to dry, and then replace the core and laminate a new inner skin, probably 2 layers of 6-inch cloth, lapping on to the edge flange, which is a little thin for my taste. A couple coats of paint and she'll be good as new, actually better.