Walkways laid with mortar may look elegant and neat at the beginning, but you will soon find that dirt, algae, and moss accumulate around the grout. Not only does this have an aesthetic impact that many will find displeasing, but there is also a more urgent reason to keep the grout in your walkway clean — failing to do so many make it slippery, and therewith dangerous.
Enlisting the help of a pressure washer is one option. You will not have to rely on any cleaning agents, and the neutral pH value of water means you won’t damage the mortar or the surrounding soil. The enormous forces of a pressure washer may, on the other hand, cause mortar to break loose over time, and the grout will have to be replaced sooner or later.
The gentlest way to clean the grout in your walkway would be to use a carbon steel wire brush to dislodge the buildup and then to hose the walkway down with an ordinary hose. Although this has the disadvantage of taking a long time, it will preserve your grout and is a perfectly valid choice for shorter walkways. By cleaning the grout in your walkway often, you’ll make your job easier, as there will be little to do each time.