Red Wing Potteries closed in 1967, long before automatic dishwashers were widely available. It’s recommended that all the dishes be washed by hand with a mild detergent.
Cracks & Crazing: Dishes often get cracks, some of which go all the way through and some just part way through. Many pieces also get superficial crazing, which are little “spiderweb” cracks that just go through the glaze and not the clay. And those cracks collect dirt, which makes them stand out all the more.
Some have had success with hydrogen peroxide. Soak the piece in equal parts of hydrogen peroxide and water for 24 hours. Once it’s done soaking, put it in a bath of pure water for an equal amount of time. This will draw the dirt out of the cracks and make the piece look better. Repeat, as necessary, for stubborn crazing.
Don’t try this technique with bleach as that tends to eat away at the clay. And don’t do this to pieces that you intend to sell –it’s considered doctoring and buyers will wonder what other defects you’re trying to hide. It’s always better to err on the side of honesty and present the piece in its natural state.