Just having taken delivery of my 2 year old, it's in beautifully prepared condition, BUT, the calipers are a bit dusty. 

 

What's good for cleaning them down? 

I'd start with something like Bilberry wheel cleaner applied with a sprayer then left to soak which you can use on the wheels too. Apply some more then agitate with a detailing brush. If that didn't work you could try one of the harsher acidic/alkaline wheel cleaners. Once clean coat with carbon collective wheel sealer so they are then easier to keep clean. If there are other alternatives the guru's on here will add to the above for you.

P.s. make sure they are cold before you start.

Wheels off, APC and a detailing brush.

Wheel off, Wonderwheels £4 from the supermarket.

 

Agitate with a brush and hose / power wash off - Don't get on the pads as it'll eat them!

I've put nothing on my callipers sealant wise but wash them properly twice a year when I swap my wheels and they clean up a treat with just car shampoo. The easy to get at bits get cleaned when I'm washing through the wheels. Again just normal shampoo and a plastic swaged paint brush