Salt frozen?

The drink is usually served either shaken with ice, on the rocks, or blended with ice, the "frozen margarita". All three are frequently served with salt on the rim of the glass. Bartenders specializing in tequila have the opinion that sugar hides the inferior flavour of bad Margaritas made by not-so-good tequilas. For people who insist on a sugar rim, the bartender typically only coats half the glass, so that they can still taste the drink without being obscured by the sugar's taste.