When I make my alkanet oil, I put an oz of the powder into a cup of oil (into a jar) and leave it for "some time" in a warm place and give it a shake every time I go past it. After a few weeks or when it seems to have taken on all the colour it is going to I will let it sit for a week and the powder settles to the bottom of the jar in an almost solid state, leaving the oil clear above it. I can carefully decant it with no need to filter it. I do waste a little at the bottom of the jar so as not to disturb the residue but that is minimal.
I am applying it as a first coat on the stock which is also being used as a wet sanding oil at that stage so there is no concern that I have seen with anything that might have escaped the settling process in the decanting process.