When washing your uncoated tin for the first time, hand wash in hot soapy water. Ideally dry them in a cooling oven. Once you have dried the tins, grease them up before every bake untill a residue has built up then grease again as required.
Many people don’t wash the tin between bakes as this helps avoid the dough sticking, much like your favourite black iron pan.
IMPORTANT: DO NOT PLACE THE BREAD TIN, OR BAKING TIN, IN A DISHWASER AT ANY TIME. THE HARSH CHEMICALS WILL EAT INTO THE TIN AND DAMAGE IT.