Block Paving Sand Problem

You could try soap and water (washing powder) and using a hard floor brush. May have to repeat the process until clean. If not, then ask your local builders merchants about any products that cleans and neutralises salt. Once you are happy re sand the drive with kiln dried sand from builders merchants. Remember, apply the sand on a DRY SUNNY DAY :) Acid not recommended for block paving as it could damage it's appearance, usually used for cleaning dried cement splashes not salt.

A normal jet wash will not remove the marking but brick acid and a 3000psi jet wash will remove markings easily

What ever you do do not power wash the driveway as it will remove the sand from underneath and cause the blocks To be on stable and eventually cause sinkage

Hi there, I would also agree with 247enviromental's answer, brick acid seems the best solution and a hard brush and plenty of attention form the jet wash. Just ensure the acid is a diluted mixture with water to prevent a bleaching affect. I would also recommend once you have completed this and have re-sanded the blocks on a dry surface, perhaps a driveway sealer to extend the un-likenesses of maintenance. Best of luck, do let us know how you get on!

I’ve never heard of this method, is the pressure washer you’re using powerful? I more powerful one may do the trick be careful not to put too much pressure on it as it could compromise the blocks. Is the block a white covered effect? This could be down to efflorescence in which case no amount of acid or jetting will remove this as it’s a chemical reaction in the block. There are products out there that that guarantee against this. It would be useful to find out if it is efflorescence or something else.