Ultraviolet Spy Pen - $9.95 Do you long to be a s...  ...with that slight constipation problem. Yippee for invisible ink

Some types of invisible ink are right there in your kitchen cupboard! Hundr...  ...to specially formulated chemicals, can be used as invisible ink . Here we explore six of the most interesting and...  ...es. We hope you’ll be inspired to make your own invisible ink at home....