Pelikan 4001 Brilliant Red tends to leave unsightly deposits with a green sheen and can clog the feed so that the nib jams; in one case the ink damaged a Lamy pen so badly that it had to be discarded. In general, coloured inks, especially red, are more aggressive than royal blue. The recommendation is to use red ink only in inexpensive pens or in models without sight window like the Waterman Serenitè and to flush the pen every few weeks during heavy use. As alternative reds with better behaviour, Private Reserve Dakota Red, Private Reserve Orange Crush, Diamine Monaco Red and Bordeaux-coloured Montblanc ink and inks from Jansen are regarded.