apartment therapy changing the world, one room at a time

Here's a ridiculous one - I unfortunately had to sacrifice the life of a moth that I could not provoke to fly back out the window. After being swatted, it fluttered to the top of my bed, where it left a small oil-like dot on the duvet cover. Instant karma. I usually can search the type of stain for a foolproof removal technique, but have no idea what this fluid was, or how to remove it. Most generally, I would say it's an organic matter. Any guaranteed general stain removal methods/products?