1. Wrap cloves, cinnamon and zest in a piece of rinsed cheesecloth. Gather into a bundle; tie with kitchen string.
2. Bring 8 cups water to a boil in a pan. Add spice bundle and tea bags. Remove from heat; cover and steep for 10 minutes.
3. Remove and discard spice bundle and tea bags. Stir in sugar until dissolved; let cool. Cover and chill for 2 hours. Serve over ice, garnished with lemon slices, if desired.