'Christmas' driftwood mounts 3 and a ? about old cork mounts

[Posey]

I haven't been growing orchids much more than 3 years and have never before had any on old cork before these two. I finally decided the old cork must be the reason these two were not doing well with old growth and the new fans would die off when their roots turned back and touched the mount. Well heck, I dunno. They are in a root growth spurt now, with the move to the new greenhouse, so I remounted em today. They don't look so sick on the classy driftwood. LOL. Could you please tell me if old cork can accumulate things that are toxic or detrimental to new and existing growth??? TIA.

This mount is 26" long. There is a lot of coconut fiber, teased up, around these for now because of their sickly condition. The bottom one is Aerangis splendida and the top one is Aerangis kirkii.