Select limes that are glossy and light to deep green in color. Limes should have a thin, smooth skin and be heavy for their size. Small brown areas on the skin should not affect flavor, but large blemishes or soft spots indicate a damaged lime. Ripe limes are firm, but not hard. Avoid limes that have a yellowish skin or are too small. A hard shriveled skin is a sign of dryness, as is a coarse thick skin. Limes are available year round in most supermarkets.