If your house in anything like mine, you've probably noticed that your houseplants collect a fine layer of dust on the leaves dulling their appearance. Although wiping them down with a soft, damp cloth makes some improvement, I've discovered that it isn't always enough. To restore the natural shine of leaves, you need to go a step further. I use a dab of mayonnaise as a natural leaf shine and it works wonders - but you do need to use caution not to get the mayonnaise on the underside of the leaves as this will block the openings the plant uses to breathe.
I've been using mayonnaise for years on my houseplants and have never had an issue, however some have reported that is damaged their leaves. Although I suspect these reports are from people who mistakenly coated the undersides of the leaves with mayonnaise - I urge you to try this method out on a leaf or two before doing your whole plant.
I find that mayonnaise works well to shine the leaves of waxy-leafed plants like philodendron and pothos, and even does a great job on my peace lily.