Razor blades. You can find ways to modify them to remove one of the edges and add a handle, though students are pretty skilled with these blades. Dull blades should be discarded – because students need to apply more pressure when using them, there is a greater risk of slipping and thus of cuts. Sharp tools are much safer. For dissection, find a way to attach a handle to the blade to increase the pressure the student is able to safely apply to the cutting point.