Definitely honey and lemon with a bit of water, used as a spritz before you sit outside in the sun a few days a week. should lighten your hair gently over time. honey added to water starts up a chemical reaction which produces teensy amounts of peroxide, which lightens hair. it's totally safe on the hair, unless you're a baby, in which case ingestion of honey could kill you (honey is toxic to babies). but if you're reading / typing on this board, that should clear you from that category, lol!
+ honey is a humectant, similar to glycerin in the way it draws moisture from the air into the hair. when combined with lemon juice it'll cancel out lemon juice's drying effects.