Pick heads that are firm. Do not buy garlic that has green growth. Also, avoid any garlic that appears musty. Squeeze garlic heads, if any of the cloves yeild, the garlic is past its prime. Store in a cool, dark bin.
Remove cloves from the head. Press the flat of a knive onto clove to loosen skin. To roast garlic, break up a head of garlic into cloves. Do not peel, but slice off the wide end of each clove. Place garlic on a double layer of foil. Drizzle with olive oil and seal tightly. Bake in a 350 degree F oven for 15 minutes. Slip tender cloves from their skins and mashe, then spread on toasted French bread or blend in mashed potatoes.