Oil-based ink, used in pre-inked stamps, are water-resistant, as well as most soaps and detergents. As such, extra care should be taken when using pre-inked stamps, so as not to damage your clothing. Water-based inks, used in self-inking stamps, are not permanent and can be removed using soaps and detergents. Quick-dry inks (Multisurface, Industrial, or Aero inks) have an alcohol base, so extra care should be taken, both with self-inking and pre-inked stamps.