dissolve 1 box of Jello in 1 cup boiling water, stir well making sure all Jello crystals are dissolved pour into container

repeat above step for all 4 boxes of Jello, chill until set and firm

after Jello is set, cut into small cubes

carefully mix all Jello cubes in a 9x13 pan, spread out evenly

in a bowl sprinkle 2 envelopes of unflavored gelatin into 1/2 cup cold water

once gelatin "swells" add 1 1/2 cups boiling water stir well to dissolve

add the can of condensed milk stir and cool (so it won't melt the Jello cubes, but not set the milk mixture...10 minutes)

gently (so not to create too many bubbles) pour milk mixture over Jello cubes

gently "shake and tap" pan to help air bubbles raise to the top

skim off as much of the air bubbles as you can

chill overnight, cut into cubes or fun shapes