Permanent Marker Art By Heike Weber

Removal
Most brands of "permanent" marker wipe off easily with acetone free nail polish remover, the kind containing ethyl acetate.
These markers are generally not truly permanent, on hard, non-porous surfaces, because instead of staining they form a surface layer that can be removed by high pressure cleaning or paint thinning solvents such as acetone, and they will eventually wear away over time, or fade in sunlight.