Yes, absolutely, we encourage it. Doodling with your 3Doodler Start directly onto your other plastic toys, such as LEGO or PlayMobil, will not damage the other toys. Your Doodle will adhere nicely to the toys, but is still removable by hand without damaging your toy.
The 3Doodler Start Eco-Plastic will stick more firmly to some clear plastic materials, such as polycarbonate & PET, but is ultimately still removable with some effort. Note that it may leave marks behind.