Reducing quantity of alkali metals

Require a workable, uncomplicated solution for reducing the amount of alkali metals (namely K, potassium) in cashew nut (Anacardium occidentale) shell liquid. Cashew nut shell liquid is a viscous brown liquid from the pericarp of the nut. Naturally occurring level of K is between 4000~5000ppm. Aim is to achieve maximum K level of 150ppm using uncomplicated, low cost method which can be replicated on an industrial scale. Already experimented with organic acid agitation, multiple water wash and evaporation technique but it's too laborious and time/cost unfeasible. Should the suggested technique be applicable in actual production process, we can offer a perpetual commission payment for as long as its being implemented.