We don't recommend washing the cheese moulds in the dishwasher as the high temperature could deform the mould.
Therefore, just hand wash in warm water with soap and then before you use them sterilise with iodophor and leave to drip dry. If you don't have iodophor, then boiling water will do the trick, just be sure to remould them into shape if they warp, before they cool and remain warped.