I'm still trying to solve the problem of weeds and moss growing in the sand-gaps on our brick-paved drive. After advice here I decided against spraying with a sealant, because of its appearance and its temporary effect. I spent a day scraping out most of it and then, after drying, sweeping in new sand.
Is there perhaps some chemical I can sweep in over the sand which will kill at least the MOSS? (The weeds and grass are sparse, and relatively easy to remove manually.)