Make a Mold Easy
The easiest to use and REUSE modling compound I've found!
Oyumaru Molding Material.
Heat in water, mold and cool. It's as simple as that! To reuse you just repeat the same steps!
Some clays may need a spritz of water in the mold or a dusting of baking soda to help the clay release well.
https://qoo.ly/3cxaij