Solvents!

When it comes to manipulating cheap plastic, foams and rubbers (I'm making these creepy dolls) solvents are the coolest. When you use super glue on the type of rubber they use for those squishy stressball things it turns it into a putty that get your hands really disgusting afterwards but I think it's worth it (especially since I secretly love nibbling Super Glue off of my fingers afterwards). Try different sorts of solvents on all different sorts of materials. Fun. I've found some pretty neat reactions and it

always lends maluability.