Place bread slices on a large baking tray. If it's a loaf cut into smaller pieces using your hands and place on a large baking tray. Place in a preheated oven and bake on medium low heat till bread becomes very crispy. Remove from oven,allow to cool completely. Place in a dry mill,add the thyme and oregano and grind till smooth. Another alternative is to pound the bread in a mortar and sieve to remove particles.