Marker pen stain on polished porcelain

[Ajax123]

Nail varnish remover.

Yep nail polish remover which contains acetone which is a great ink solvent.

 

[molly09]

A significant portion of the alcohol-based solvents in hairspray are ideal for removing permanent marker ink from ceramic and other nonporous surfaces.

 

[Beechy]

Try using hand sanitiser gel

 

[Jannere]

Acetone, alcohol, chlorine or if these agents won't help, you may polish that place from marker and then cover greedily.