Two high cards: which two?
When there is no pair and no real draw, high cards are the fallback — jack, queen, king, ace. Two high cards beat one, and if two of them share a suit they are also two cards to a royal, which is better still.
With three high cards in different suits, keep only two, and the one you drop is the ace. A-K-Q becomes K-Q. A-K-J becomes K-J. A-Q-J becomes Q-J. Nothing outranks an ace, so it is the worst of the four for making a straight. The one exception is jack-queen-king — those three high cards all stay.
Example: A♠ K♦ Q♥ 7♣ 3♦. Hold K♦ Q♥ and let the ace go. K♦ Q♥ returns about 0.48 coins per coin bet, A♠ K♦ about 0.47, and all three together only 0.46.
Suited changes the answer. A♠ K♠ is worth about 0.59 against 0.48 for A♠ K♦ — so when two high cards share a suit, those are the two you keep, ace included. A suited ten counts here too: T♥ J♥ is worth about 0.51, better than the jack on its own.
Chart lines
Coach
Deal a hand, keep the cards you want, then draw. This panel names the best hold and what anything else would have cost you.