Warm soapy water and a damp micro fibre cloth will have them looking like new. Just don't get them too wet. Damp cloth, then rinse the cloth clean in the warm soapy water, ring out and rub away again. When clean, dry as much as you can with a dry micro fibre cloth, then leave the rest to dry on its own. Buff the slight pile up when dry with a dry micro fibre cloth. Cheers Jon