If anything sticky ever spilled on the remote, the top of the membrane will be a mess. Use a Q-tip and water to gently clean the mess. Avoid touching the bottom of the membrane, to avoid contaminating the membrane contacts with oil from your skin.

If the membrane is dusty but not sticky, use compressed air or a small vacuum to clear it away.

Inspect the contact pads on the bottom of the membrane. They should look uniformly dull and clean. If any of them look shiny compared to the rest, they may be contaminated and need to be cleaned.

To clean a contact pad, use a Q-tip moistened with rubbing alcohol. Rub the contact gently. You don't want to rub off any of the conductive paint, because that will prevent the key from firing.

Make note of any membrane contacts that look worn or where conducting paint is missing. We will deal with them later.