siding

The house has that powder coated siding with silver aluminum under, 6" laps. The paint is peeling off and the silver is showing. How to re-paint these sections or put new panels on? I believe its called factory coated siding? We had the roof redone and the siding is white, the shingles black and so the siding is pretty nasty looking from the black dust when it rain coming down the siding, but can't obviously power wash if the paints peeling off sections of the siding. Any suggestions on that too?