I have thrown everything but the kitchen sink at them
including powerwashing.
I was wondering if anyone has a method
I haven't tried yet???

cast iron I am assuming? what about glassbeading?

they are still on the car,i don't want to take it that far
just looking for a easier way to clean them up
as they get dirty fast and are hard to clean.

maybe try some of this.

https://www.washyourcar.com/products/bra...CFUlNfgodYpEL7Q

i myself haven't used i, got the link from another message board. several comments state it works good.

The calipers on my slk55 amg, are nice painted with AMG logo on them - about once a month I will take the wheels off the car, clean the inside of the wheels, wax them (makes getting the grime off with just washing, wayyy easier) . . . at same times, just take soap & water to clean up the calipers - brake dust just washes away . . .

Back in the day I used to help clean up cars for the auction. First thing I was told, soap first, not water, we usually used white wall cleaner for things under the hood, do not let it dry, wipe with a brush then water off the area. Tires, wheels, calipers are done the same way, I carry that over to everything I wash, even my hands. Don't know why but it works, again if you wet it first it won't come clean. Doing that way I have no problem using the regular spray cleaners. If it doesn't come clean the first time, let dry completely then apply again.

I don't have Brembo brake calipers but I just finished putting on a set of Power Stops on my 300C by Rockauto. Essentially the same deal, I believe which is powder coated brake calipers. I just spray them with Meguiar's Hot Rims wheel cleaner and leave on for 5 minutes and then hose off. They turn out spotless although rust will start forming on your rotors because of the cleaning action. First application of your brakes will scuff off that rust and your calipers will be gleaming.