What Kind of Liquid Can You Use to Clean Mildew From the Gutters?

Hose Jet

• Clean out any debris that's in your gutter using a trowel, spade and rubber gloves. Dump the debris in a bucket for easier cleanup later. Once it's relatively clean, turn your garden hose nozzle's setting to its most powerful setting, usually jet or stream. Spray any mildew in the gutter at an angle away from yourself so you don't get splashed. Wear goggles or glasses anyway just in case. Keep spraying until you see no visible gunk or potential mildew still clinging to the inside of the gutter.

Bleach

• Mix a small amount of bleach in a bucket of water using proportions suggested on the bleach label for household mildew removal. Wear rubber gloves, and pour a bit of the bleach mixture directly onto the mildewed area of the gutter. Scrub with a firm brush. If the mildew is on the outside of the gutter, put a bit of the bleach solution in a spray bottle and spray it on the problem area. Remove or cover any areas that could be stained by the bleach first.

Commercial Mildew Killers/Bleach Activators

• Home improvement stores sell mold and mildew killers designed for exterior surfaces such as decks, gutters and siding. Many of these, such as Jomax, feature a bleach activator, which improves the effectiveness of a bleach and water solution. Mix the chemical with water and bleach as indicated on the mildew cleaner container. Apply with a garden sprayer after cleaning and rinsing as much residue out of the gutters as possible.

Pressure Washing Solutions

• Many pressure washers have extension attachments, which are ideal for reaching inside gutters. Some even have gutter-specific wands and flexible ends that will tackle the task a bit better. Assemble the pressure-washing wand and attachments as directed by the manufacturer's instructions. Spray the gutters down first with water and follow with the cleaning solution recommended by the pressure washer instructions. Follow up with the rinsing solution offered by your pressure washer's manufacturer.