Coins are best kept in mahogony cabinets as fruit woods can react with them and damage their surface. Copper and bronze coins can be cleaned with a bristle brush. Silver coins should only be washed in soap and water and dried with a soft duster. Avoid using acids, such as vinegar, as they can etch into the surface of the coin. Never wash enamels because they usually have iron bases which will corrode and shed the enamel.
Ivory is a highly sensitive material which absorbs water.
Keep away from sunlight and hot radiators. A soft brush will remove most grime or you can use cotton buds dipped in methylated spirit. Only clean silver when absolutely necessary. Wash in hot water with a little washing up liquid and dry with a soft cloth. And don't put elastic bands around silver, as they corrode it.