Your clean dry fingers. Have 2 bowls. Cup your open dominant hand like Shaq palming a basketball, with your palm up. Pour slowly into it. Wriggle your fingers and palm as necessary to catch the pretzels and let the rest pass. Pause to toss the pretzels into the reject bowl. If necessary, pick out the few that escaped into the keep bowl. Then pour a little more. Continue until the bag is empty, then pour the keeps back into the bag. You may now lick the salt off your hand. I suppose you could try using crushed pretzel bits as fried-chicken breadcrumbs, but cut back on salt.