I’m getting ready to soon do a go over on the 2017 Cabrio and I know the roof slide rails need a good cleaning and lube . I’m wondering how DIY owners are tackling this. What cleaner , technique, lube choices and helpful hints can be shared . My top is getting a bit noisy on its retreat to the down position . It visually looks dirty , and I’m sure that the factory lube as attracted dirt while in the open roof mode .