[Slick]

Is it safe to wax the bumpers? I'm leery of waxing anything non-metal.

[Money]

Your not really waxing the material (the plastic they're made of), your waxing the paint.

These guys have a lot of good information about interior/exterior car care: http://www.properautocare.com/exteriorcare.html

[Jim D.]

Same logic goes for the wheels... they're aluminum, but don't use a metal polish.

Most polished, natural finish or painted factory wheels have a plasticized clearcoat (slightly different than your body paint), and a fine plastic polish is ideal (Mothers is excellent); or a synthetic wax also works good.

Routinely, if nothing else, a wiping with your instant detailer or a spray wax when you finish the rest of the car will do wonders.

Frequent washing of the wheels will help keep brake dust from damaging the clearcoat so you'll need to worry about the above steps a little less. When necessary, use an all-wheel cleaner (safe for clearcoats) and a soft wheel brush or an old wash mitt to remove the grunge, but hopefully they'll never get that bad.