[Coral-List] Info/references on coral skeleton cleaning protocols

[Sam Kahng]

Dear Coral-listers,
 
We are seeking ways in which to thoroughly clean coral skeletons in preparation to measure high precision optical properties (with the calcium carbonate structure in tact). Apparently repeated, rigorous bleaching and rinsing with sodium hypochlorite and distilled water does not remove all organic matter (or at least all combustible carbon). High temperature combustion does remove the remaining organic carbon but leaves a significant amount grey ash residue integrated in the skeletal matrix. If anyone knows of any cleaning protocols that can effectively remove all organic matter without altering the microscale structural integrity of the calcium carbonate skeleton, I would appreciate any leads. Alternatively, we are interested in any effective protocol for cleaning post-combustion ash residue from the calcium carbonate skeleton. I am not a geochemist so I suspect we are missing a number of considerations. 
 
Mahalo for your assistance,
Sam