Gravestones and other monuments usually have text deeply engraved into them, which is a great way to ensure the message remains for many years after it's created. Over time, however, moss, lichen and the effects of weathering can make it more difficult to read. When this happens, the monument isn't looking its best, and anyone viewing it won't be able to see what its purpose is or whose memory it marks. You may need monument restorations depending on the damage, but in some cases you can do some maintenance yourself.
Luckily, it's not too difficult to make engraved text readable again and to make sure it stays that way.
Pick off any moss
When there are large pieces of moss, they can simply be pulled off with your hands, wearing gloves if you prefer. Don't worry about any that you can't get to, as you'll deal with those in the next few steps. Once the larger patches of moss are gone, you should already start to see quite a difference.
Give it a gentle scrub
Start with an ordinary dry toothbrush and gently work it into all of the engraved lettering to remove smaller bits of moss and other growth. If a toothbrush doesn't seem to be firm enough, try using a small wire brush, but be very gentle as some types of stone can be damaged more easily than you might think. Don't worry if it's not perfect yet, and take care not to overdo the brushing.
If you need more power still, you can use a knife, but go for a blunt knife rather than anything sharp. Again, be very gentle and don't scratch at the stone.
Wash it down
Make a half and half mixture of bleach and hot water and sponge the whole surface of the stone, making sure it soaks into the engraving. Get your toothbrush or wire brush and start scrubbing gently once again, which should get rid of the last bits. If your brush gets dirty, swirl it in the bleach mixture and carry on, ensuring it doesn't dry out while you're still cleaning.
Bleach can sometimes leave marks on stone, but they'll wash off with some soapy water. Make sure you rinse it well after any sort of washing.
Stop it coming back
Bleach is not just good for cleaning; it should also inhibit growth for a little while. You might find it useful to brush some bleach and water solution into the lettering once a week or so, which is normally enough to keep it clear and easy to read.