Best Way To Clean Sand-wash Drive-way

[Sir Burr]

Well, rainy season is over and it's time to pressure wash my drive-way, which I do once a year.

This year, pressure washing is not so effective as last year. Some of the mould is getting entreched. By the way, the drive-way is fairly coarse sand-wash.

Does anyone have a better idea on how to clean sand-wash?

I have heard of acid wash. What is it? How do you use it?

[monty]

You can use hydrochloric acid. Available in all swimming pool supply shops, around 300 Baht/20 liters.

Is also excellent to clean cement stains, or iron stains (like the ones you get if you have a sprinkler installation, and your water contains a lot of dissolved iron).

Be sure to use safety goggles and protective clothing. Once in contact with your driveway it will start fuming and give of highly toxic gases! Take wind direction in consideration. Also, if these fumes come into contact with for example a stainless steel gate, it'll cause severe corrosion!

Remove with lots and lots of water...