[Sci-Fi]

My experiences only:
P21S wheel cleaner or S100 wheel cleaner is the safest, but may be too mild for some people. Meguiar's APC+, diluted 4:1 (4 parts water to one part APC+), makes an excellent and safe wheel cleaner. Eagle One A2Z is probably the strongest product you want to use, BUT follow the directions carefully and there is a WARNING: Do not use on non-factory painted wheels, motorcycle wheels, and some anodized wheels. The reason for the warning is that, in some cases, you may experience staining or removal of paint/clearcoat.

There are a lot of wheel cleaning products out there. Read the label and instructions carefully for the wheel cleaning product you wish to use. Try to buy the one that is clearcoat safe. The stronger ones may contain acid (Just FYI: many citrus based cleaners are acidic in nature). But since you are trading the car in, it may not matter, since you want to clean it up as fast as possible.

It is ofter better to use a clay bar (dedicated only for wheel use) after washing the wheels or wheel covers with car wash and/or wheel cleaner to remove any remaining brake dust. Then apply a sealant/synthetic or your favorite wax on the wheels for protection and it will make it easier to clean your wheels the next time around. Many auto supply stores carry small slip-on your finger cleaning foam pads/sponges and those are helpful in cleaning hard to reach areas and are relatively cheap to buy.