Concrete out here doesn't just get dirty, it grows things. Algae and moss root into the surface and turn it black and green. Add tire marks, oil drips and whatever's dripped off the car all winter, and a five-year-old driveway looks twenty.
Most people assume it's stained permanently. It usually isn't.
How it's done
A note on pavers
Concrete is one of the few surfaces that genuinely wants pressure. I use a surface cleaner — a flat spinning head that covers the slab evenly — rather than waving a wand around, which is what leaves those zebra stripes you see on half the driveways in town.
Heavier growth gets treated first so it releases instead of being blasted at. Then the whole surface is cleaned in one even pass, edges and cracks detailed by hand, and the whole thing rinsed off.
What I clean: driveways · walkways and paths · patios and pool decks · stairs and landings · pavers and interlocking brick · exposed aggregate · retaining walls
Pavers need a lighter touch than a poured slab — too much pressure blows the sand out of the joints and loosens the whole surface. If you've got pavers, say so when you call and I'll plan for it.