Q.Something I Read In A Book
I recently read a book by Elizabeth Gilbert called The Signature of All Things. In it, one the the characters cleans and polishes orchid leaves using a banana peel. I have never heard of this. My questions is: if this is possible, is the inside or the outside of the peel used? thank you in advance,

Certified GKH Gardening Expert
This is so that they can absorb the potassium, though this is not the most effective method by which to do so. Drying and powdering the peels, then foliar spraying is a better method, since it will make the potassium much more easily available.
If you still choose to wipe the leaves, simply use the inside of the peel.
Here is an article for more information on the care of Orchids:
https://www.gardeningknowhow.com/ornamental/flowers/orchids/indoor-orchid-care.htm