after flushing the nib with distilled water, I find flushing it with eye glass (spectacle) lens cleaning solution, to be very good, followed by
further distilled water rinse.
the surfactants used in the lens cleaning solution are quite mild and perfect to help clean the nib and feed system.
does not contain solvents and is an aqueous solution.
anyone using other diy solutions(excuse the pun) I would be interested to hear.
NOTE I do not mean contact lens cleaning solution that contains water soluble gums.