Dentures need to be kept moist, otherwise they' will lose their shape. They can be soaked in a special cleanser diluted in water for example the Polident denture cleanser, it's in tablet form and you may dissolve half of it in water then soak denture overnight or in a mix of warm water and vinegar (half and half) but only ...for 25 to 30minutes. Vinegar has been demonstrated to be effective in killing the types of microorganisms that reside on the surface of dentures, effective way to remove tartar accumulation.
Warning! But don’t use vinegar in dentures with metal clasps or metal framework for it may tarnish the metal component of partial dentures.
Or soak it in 2 teaspoons baking soda dissolved in a glass or small bowl of warm water (30 minutes). The baking soda loosens food particles and neutralizes odors to keep appliances fresh.
Or just use regular tap water, soak denture overnight when not in use
Rinse your dentures thoroughly .Use cool or warm water. But never use hot water,it can distort/deform shape of your dentures. Just like your natural teeth, brush your dentures everyday with a toothbrush and toothpaste.