We recommend using a baby bottle steriliser, then placing the crock and weights in an oven at 110ºC/230°F for about 10 minutes to fully dry them.
Alternatively, you can boil and soak the weights in vinegar to inhibit mould growth.
Try your best to ensure you're as sterile as possible during fermenting in the crock, especially when checking on it, to avoid mould growth to start with.