Patina--vinegar (white or apple cider) and salt. For small items, fill a quart yogurt container half full of vinegar, and sprinkle in about 1 tsp salt. Add any metal you want to 'age'. Seal if you touch items a lot
This would be a neat Valentine's Day gift. if I could bring myself to punch holes in a book. Maybe I could use old magazines instead. Punch a hole in the shape of a heart into an old book and arrange them into a frame for a decoration.