You've got to remove the visible paint and also the coatings underneath to get to bare metal. My assumption is that the original clear powdercoat (I think that was used from the factory but others can correct me if I'm wrong) is still partially intact so may need to be removed once the visible paint is off depending on it's condition. The Lexus wheels also had paint in the D holes and those grooves.
My guess is that the visible paint will be the easiest to get off and may come off with fairly gentle solvents/strippers while the underlying coatings will be harder to remove and may benefit from media blasting or other techniques. I'm sharing that since you may want to try a few "easy" approaches on a spot first to get a sense for what it takes to get the visible coating off. If, by some chance, the wheels look ok under the paint you could possibly get away from a little cleaning and then clear-coat touch up on problem areas if there aren't too many.
There's a guy on the forum with a great wheel refinishing setup that will make them like new for a reasonable price. I don't have a name or link handy but wanted to share in case you prefer to just have them done for you.