Not 100% positive what you're asking but I've never seen the need to use any kind of conditioner or lubricant on ukulele strings. Most are either nylon or fluorocarbon and will not corrode. Even a metal-wound string shouldn't be a problem unless you're leaving it on for years (or in a corrosive environment). When I played guitar, I did occasionally use a string conditioner/cleaner but even then it may have been more of a psychological thing rather than a practical need. Just wipe them down with a damp cloth to remove any crud and play on!