If you can get NaNO2, you can add 50g to 16oz of water, and then pour the afformentioned ether-hexane-oil mixture in also to create a two phase mixture. Then gradually pour in small amounts of dilute H2SO4 (calculate the exact amount needed to react with the NaNO2 and don't add any more) while swirling the container. Alternatively, you can drop the H2SO4 in over several hours while stirring with a magnetic stirrer. Its not really clear whether either method has better yields overall, but it appears the N2O3 method works better with calamus oil/herb.