We have a bench, a rather sad bench, covered in lichen.
We will let it dry, clean off the last bits of lichen, wash it down and then it can be oiled. Big really worked hard and happily at a not terribly nice job. I think she found it very rewarding seeing the improvement she had achieved.
Next, she can clean out the gutters for me.
we use covers on our garden furniture – they do prolong the need to do the oiling quite so often.