Cleaning patio, path, driveway

[Dilbertian]

The options appear to be herbicidal/algaecidal spray or pressure washer.

Which is the more ecologically sound method?

I'm thinking pressure washer. But is there something better?

Would a bucket of water and a stiff brush do it?

But yes, pressure washer would be better than using chemicals if job needs more than elbow grease!

We used a pressure washer on our very dirty Indian Sandstone and it worked extremely well. Water only. There are a few small patches left which I plan to clean with a scrubbing brush. I researched the so-called 'safe' sprays and solutions but if it kills algae, what else does it poison? And when they tell you not to let your pet walk on it until it has dried you know that there's a problem!

I always use my pressure washer. Our solar panels reduce our carbon footprint for the electricity used, and we are most definitely not short of water right now.

@SignOnTheWindow

Would a bucket of water and a stiff brush do it?

It would require more elbow grease than I possess!

Dh borrowed a pressure washer for our terrace and it's broken up quite a bit! I tried using very hot vinegar water with a scrubbing brush, it worked against the rain stains BUT it's labour intensive! And the stains have returned of course.