We had new concrete pavers installed in a patio and need to clean the effloresence off them before sealing. Also had polymeric sand placed between the pavers. If I use 5 pct household vinegar and a stiff brush and rinse off well with a hose, do I need to use a neutralizer before sealing? Will vinegar harm the neighbor's roses?

Muratic acid is the most common cleaner for brick and concrete. Sold in plastic gallons at home centers and hardware stores, is quite affordable. Follow the directions. Use good rubber gloves, and stiff broom or large scrub brush. You should also use goggles. Rinse generously and get it dry completely before sealing. Vinegar, a weak acid, probably won't have much of an effect. Rinsing with lots of water will neutralize the acid and should not affect your neighbors plants. Hope this is helpful.

Had charcoal pavers installed with polymeric sand. Cleaned with muriatic acid and ready to seal but there is still grey marks where the pavers rubbed together (concrete from the bottom of the top layer onto the top of the next bottom layer) during shipping. Is there a way to get rid of the small grey marks before we seal the pavers.

A stiff nylon brush should be strong enough to get rid of concrete dust. But this might be metal scratch (like the unsightly marking you can get on a porcelain plumbing fixture.) If it's a metal scratch, use some rust remover. Hope this was helpful.

It isn't caused by metal. We used a stiff nylon brush with the 5:1 mixture of muriatic acid wash yesterday and it got rid of the efflorescence but not the grey marks which are on some of the charcoal; colored concrete pavers in a pattern which looks like the pavers on top of some pavers lower down on the pallet were rubbing and leaving a grey mark in the corners. They look fine when wet. Any other suggestions?