Correct Cards can be hidden from view or they can be removed from the deck. To remove a Card completely from the deck, simply click on the “Remove Card” button in the lower left of each Card screen.
You can also hide correct Cards from viewing and still keep them in your deck: While on the Card screen, click on the “Options” button in the upper right of the screen, then choose to “Hide correct Cards.” When you are ready to view them again, go back into the Options panel and uncheck “Hide correct Cards.”