Best way to mark cards

How to mark playing cards? How to mark cards without being found? Do you know the best way to mark cards? Take marked bicycle playing cards for example.
Bicycle cards are made of high quality plastic or best quality paper. We can use card marking ink to make a marked deck of cards Bicycle. Cards marking kit is obvious. If you ask me how to mark cards while playing poker, I think it is not good idea.
How to use a marked deck while playing poker? Luminous ink contact lenses and invisible ink pen with glasses can help you.