How to mark cards

How to mark cards with invisible ink? We often buy marked cards from marked cards Amazon or marked cards store. But do you know how to mark cards while playing poker?
We have luminous ink kit for making cards that can help you mark cards. You can use small cotton to wet with invisible ink for playing cards. This process is very secret so that no one will know your trick to do with marked decks.
Marked playing poker needs skillful method. You can wear marked cards contact lenses to detest it.