Pikkie : Try a pencil. Rub the eraser onto the contacts, the tip to refill the faded carbon on the elastomeric buttons.
If not happy on longevity, punch/make aluminium foil tiny discs and glue on top of the faded carbon surfaces of the button.
If your remote shows some oily deposits on the board contacts, wash with soap, dry with a fan and reassemble, and keep the remote wrapped in the same kind of clear bag they are shipped, or on 'saran' wrap.