The keys are firmly attached to a removable board. A hose and a bit of light brushing is all it takes. There are very few crevices as they were filled. Good point though, we will recheck and epoxy any that remain.
We had access to a pile of used stuff. Old deck boards, 4x4 fence posts, several pieces of acrylic, a few pieces of galvanized roofing, random sizes of plywood, a discarded 1/2 inch thick plastic sign material, a box of hinges, some aircraft cable and a PIANO.
What could we do with it? Hmmm...