A method of continuous inkjet printing by using a printing fluid comprising water, a soluble or dispersed polymeric component, and less than a total of 10 wt % of low-volatile water soluble humectant having a boiling point of greater than 170C; ejecting spaced droplets from a printhead and controlling the spaced droplets to mark a substrate; stopping delivery of the printing fluid to the printhead; and then delivering the maintenance fluid from the maintenance fluid supply to the printhead to purge the printing fluid from the printhead, with the maintenance fluid comprising water and at least 5 wt % low-volatile water soluble humectant having a boiling point of greater than 170C, wherein the concentration of low-volatile water soluble humectant in the maintenance fluid is greater than that in the printing fluid to purge the printing fluid from the printhead.