A permanent marker is a felt tip pen using indelible ink that writes on most surfaces, even glass or polished surfaces. The ink in permanent markers is waterproof and cannot be washed off with water.
Permanent markers use ink that is non-polar, or has an equally distributed electron charge in the molecules. Water is polar, meaning that the electron charge is uneven. Polar and non-polar molecules repel each other like oil and water --- therefore, water does not dissolve permanent ink.
Since permanent ink does not mix with water, when it sinks into a surface or substance, it is very difficult to remove. Vinegar and water, both polar substances, do not affect permanent ink. However, rubbing alcohol is non-polar and will dissolve permanent ink, particularly if it has not been in place long.
Non-porous, glossy items do not absorb any ink well, so even though permanent markers are waterproof, they may rub or erase off of non-porous surfaces. When used on fabric, permanent marker does not come out easily. Any markings made with permanent markers will remain after repeated washings, although the colour does eventually fade to a lighter shade.