Many years ago I read a book by Len Webber that mentioned he’d done an experiment with Ficus coronata leaves and found they were too soft to be used as sandpaper. The quote is also on Wikipedia for the species;
“A popular story holds that the fig’s leaves were used as sandpaper for polishing wood or turtle shells by indigenous people, yet when tested by Bonsai and fig enthusiast Len Webber, they were too brittle and soft to function in this fashion.“.
Since then I’ve tried the leaves of Ficus opposita and Ficus acculeata from northern Australia and they work surprisingly well as sandaper! There’s also an amazing quote from Sir Joseph Banks Journal while travelling up the east coast of Australia with Cook on the Endeavour that possibly refers to Ficus opposita;
“Besides these they use shells and corals to scrape the points of their darts, and polish them with the leaves of a kind of wild Fig tree which bites upon wood almost as keenly as our European shave grass us(e)d by the Joiners.”
It’s interesting to see how the English language has changed since these journals were written, there a lot of odd spelling i.e. usd instead of used, and I think the quote was mis interpreted and ‘grass’ should be ‘glass’.
…All this time I assumed Webber was right and F. coronata leaves didn’t work as sandpaper. I even seem to remember testing some leaves and confirming that he was right, so today I decided to try it out again and of course found, they are true to their name and do work as sandpaper! There may be situations where the leaves are more suited. The leaves from my plant have grown in full sun and the plant has been root bound for many years, it grows slowly, and the leaves have hardened off nicely.
Here’s a video of a Ficus coronata leaf sanding a branch, the wood is a dead branch from a Japanese maple if you’re interested.