Docs usually hit the panic button when your hematocrit gets in the mid 50's. Donating is the quickest way to get it down. If it's super high, the doc can prescribe therapeutic phlebotomy that is more frequent than typical donations. There is an ip6 and curcumin protocol here that you should be able to find. It will probably only bring it down a couple of points though, and is not quick. It's more something to do long term as a daily regimen like taking vitamins. You'll probably still end up needing to donate from time to time.
What's your blood work look like?