“Bulletproof” refers to any Noodler’s Ink that resists all the known tools of a forger, UV light, UV light wands, bleaches, alcohols, solvents, petrochemicals, oven cleaners, carpet cleaners, carpet stain lifters, and of course…they are also waterproof once permitted to dry upon cellulose paper. Some inks are more bulletproof than others – black being the most bulletproof of all.
As with any “bulletproof” ink we suggest you use your pen on a daily basis and clean the pen promptly if you see you will not be using it for a while. These types of inks MAY clog the pen if left in an unused pen for an extended period of time.