This is a DIY cleaning video for NES Nintendo game cartridges. Using Brasso and alcohol seems to work to clean the connectors in the cartridges. It seems Brasso will turn black even if the connectors are clean. Base the results on the cleanliness of your connectors rather than the cleanliness of the rag. Games go from broken to working. Don't use a brillo or scour pad as it may strip the metal pins in the connector.