Things You'll Need
Mr. Clean Magic Eraser (or toothpaste)
Artillery fungus is a common fungus in North America. Its primary job is to decay dead wood. In home gardens, it often takes up residence in wood mulch. When it is time for it to reproduce, the fungus lives up to its name and shoots tiny spores in all directions. These sticky, black dots cling to vinyl siding like glue. Failed attempts at power washing, bleaching and painting can make them seem like a permanent problem. If the black dots have dried, the only option has been to physically scrb them away, an onerous job that leaves stains behind. But, anecdotal evidence gathered by Dr. Donald Davis of Penn State University collected after the results of a high-school research project suggests that a combination of mouthwash and a stain eraser -- or toothpaste -- may be your best bet at removing the stubborn little buggers.
Pour mouthwash into a handheld spray bottle.
Spray the artillery fungus with the mouthwash until it is dripping wet.
Soak a few paper towels in mouthwash and use them to scrub away the little black dots, or "peridioles." It will take some elbow grease, but eventually the bulk of the masses will come off onto the paper towel.
Scrub away the stains left behind by the removed peridioles with a Mr. Clean Magic Eraser. If you cannot get hold of Mr. Clean Magic Eraser, a Brillo pad will work. But, it takes a lot more scrubbing to remove the spots. You can substitute toothpaste for the eraser.
The most effective mouthwash in the research project was Cinnamon Ice Scope Mouthwash, which removed the coats of the fungus peridioles "with little effort," while Crest MultiCare Whitening Fresh Mint Toothpaste was used to remove the stains. According to the high-school student's abstract, the "celluose in the paper towels pulls the cetylpyridinium chloride, CPC, from the mouthwash product to the site of the fungus...enabling the CPC to go into the peridiole and break down the outer shell." If the artillery fungus has been in place for a long while, it may leave a light stain behind despite your best scrubbing efforts. These light stains will fade with time. To get rid of artillery fungus in your garden mulch, switch to large pine bark nugget mulch and refresh it every year. You can power wash artillery fungus away, but only on new vinyl siding that still has a sheen to it. And even then, you might be able to remove all the fungus.