You might have wondered what those dark smudges on the window sill are: they could be spider waste. Spiders do, in fact, poop, and it’s pretty common to see their droppings on surfaces where they tend to hang out, such as corners and under webs.

In its fresh state, spider poop on window sill poop looks a bit like a black or brown splat or drip, and it can even look a little oily or wet at times. Spider waste is made up of uric acid, guanine (which comes from breaking down proteins), and any leftover bits of insect prey that the spider has consumed.

When the poop dries, it becomes more smudge-like and dark in color, and it can also get a little crusty around the edges. When cleaning up a fresh spill, it’s easy enough to simply wipe the spot with a damp cloth or rag. But if dried drops have been left behind, more intensive cleaning may be required.

How to Clean Cockroach Droppings Safely and Effectively

Before you start scrubbing, make sure you test your cleaner or cleaning product on an inconspicuous area of the surface to see how it might react. Also note whether the surface is waxed, porous, or glossy, as this will dictate the best method for removal.

Getting rid of the marks will help reduce your risk of spider infestation, but you’ll also need to take steps to make your home less attractive to these unwanted guests. Keep your house tidy, remove any piles of clothes or old boxes where spiders can hide, and seal up cracks and gaps to discourage them from finding shelter there in the first place.…