Shapeways lists the material as non Toxic, dishwasher safe but not food safe.
WSF is very porous, so if you use it for food I recommend to clean it thoroughly and seal it with a food save varnish like Press Varnish or Kelterlack. Or you can simply wrap them into aluminum foil before to using.
Rock: 5 cm / 1.9 inch
Paper: 8 cm / 3.1 inch
Scissors: 7.8 cm / 3.1 inch