When to clean up reclaimed blocks

[Gazzatron]

Hi guys. I have been given a load of old blocks that I'm putting down on my driveway. I'm almost ready to lay but I was wondering when is best to jet wash them. Individually before I lay them, once laid but before kiln dried sand goes in (could this affect the sand bed) or at the very end (could this wash out the joints) thanks in advance, Gaz.

[rxbren]

Lay,sand,wack,re-sand,jet,let dry,re-sand

[Gazzatron]

Rxbren that sounds like a plan thanks mate