I ould just wash it like any other sand or gravel... stick it in the buccket, pour water into bucket, swoosh sand around, pour water out and repeat until water runs out clear.....
Is the sand ok filter wise or does the filter become more clogged up? (external canister). When adding to a filled tank just pour in and wait to settle or drain the whole tank as much as possible?
I have had coral gravel for a year or more now. If I remember rightly I rinsed it through a couple of times and it was fine. The water will fog up a bit for a while which will do no harm. Like cycling, it seems to take an age but in the scheme of things it's soon forgotten.
Coral gravel continually produces sand partials as in nature which you will find when you gravel vac. No problem