There are two ways in which to make a scratch card by your self. The first is using scratch off tickets which are available commercially to cover cards with messages. Another simple home made method is with the use of crayons, green water colour paint, paint brush, water, black felt pen and a card to write on. The card should typically be of a plastic finish. Write the message on the card. Cover the message lightly with the green crayon and then and only then paint it over with green water colour. Let it dry. Now you can use a coin or a key to remove the paint and see your message. You can use this method to make scratch cards of your choice.