These cutters are specifically designed to work with polymer clay. FEATURES: - Extremely sharp blade of 0.3mm to ensure the cleanest cut and minimal (or none) need for sanding. - Made of PLA, a recyclable plastic - Extremely durable walls to prevent cracking and breaking We recommend to use a thinner clay slab, and to ensure the slab is sticking to the working surface well for better cutting experience. To avoid clay getting stuck inside the cutter, you can use a bit of cornstarch or baby powder by lightly brushing it on the clay before using the cutter. Achieving the same effect can be done by placing a piece of cling wrap on top of the clay. To clean your cutters, use a damp cloth or a wet tissue. Not dishwasher safe. Do not bake/heat/expose to high temperatures.