What you need to make this sensory play idea~
To make fill the molds about 3/4 full of paint then fill the rest with water and mix.
Once mixed place in freezer to set over night.
Once frozen they are ready to be played with. I had no issues with them coming out but if you find that you do, run the tray under warm water.
My daughter loved painting with them while my son liked crushing them up. As they melted it become even more fun as then the kids could paint using their hands. Making hand prints and spider were two of the big favorites. We even got in some color mixing practiced.