We recommend using the Mad Millie Steriliser and then placing the crock and weights into an oven at 110ºC/230°F for about 10 minutes to completely dry them out.
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.