TL;DR
Cut power at the breaker before touching an exterior fixture, and confirm it is off at the switch as well as the panel. Outdoor fixtures are rated for rain falling down, not for water driven sideways, so they are hand-cleaned with a damp cloth and a mild detergent -- never sprayed with a hose or a pressure washer.
Power off first, and verify it
An exterior fixture is a sealed-ish enclosure with live wiring inside. Water where the wiring is, with power on, is a shock hazard.
Turn the fixture off at its switch, then find and switch off the breaker that feeds it. Label the panel if you have not already; guessing which breaker covers the porch is how people find out the hard way.
Verify by trying the switch. The light should not come on. If the fixture is on a motion sensor or a timer, verify it is dead by another means rather than assuming.
Let the fixture cool. Bulbs and lenses that have been running get hot enough to burn, and cold water on a hot glass lens can crack it.
If you are not comfortable opening a fixture, or if the wiring inside looks damaged, corroded, or scorched, that is electrician work rather than cleaning work.
Never spray a fixture
This is the rule that gets broken during a house wash.
Exterior fixtures are gasketed against rain, which arrives falling downward at low velocity. A hose stream, and certainly a pressure washer stream, is water driven sideways with force behind it. Gaskets that are years old and slightly compressed will let that past.
Water inside the housing corrodes the socket and terminals, shorts a fixture that seemed fine at the time, and can trip a circuit weeks later. On a fixture with an electronic driver or a sensor, it kills the electronics outright.
The same applies to outlets, meter bases, doorbell hardware, and low-voltage transformers. All of them belong on the do-not-spray list, which is the wider point in surfaces you should never pressure wash.
During an exterior wash, either cut power and cover them, or work around them and hand-clean afterward. That step is part of the prep in washing vinyl siding without forcing water behind it.
What you need
- Mild dish soap and warm water in a bucket
- Two soft cloths, one for washing and one for drying
- A soft brush or an old toothbrush for corners
- A small vacuum or a dry brush for insects and debris
- Glass cleaner for clear lenses, applied to the cloth rather than sprayed
- Gloves and eye protection
Nothing abrasive. Nothing solvent-based unless the finish is confirmed to take it.
The method
1. Power off and verified. Fixture cool.
2. Dry-clean first. Brush or vacuum out cobwebs, insect debris, and leaf litter. Exterior fixtures accumulate a surprising amount of dead insects, and getting them out dry is far easier than washing them into a paste.
3. Open the fixture if it opens. Many have a removable lens or a glass panel held by thumbscrews or clips. Note how it comes apart. Set fasteners somewhere they will not roll away.
4. Wash the lens or glass separately. In a sink or a bucket, with mild soap and warm water. Dry it completely before reassembly, because trapped moisture will fog the lens from the inside.
5. Wipe the housing with a damp cloth, not a wet one. Wring it out. Work into corners with a soft brush.
6. Wipe the bulb only when cool and only if dry. Dust on a bulb reduces output noticeably. Never wipe a warm bulb with a damp cloth.
7. Dry everything fully before reassembly. This is the step people skip and regret.
8. Reassemble, then restore power at the breaker.
Source: general lighting fixture care and electrical safety guidance
Cleaning by finish
Painted metal takes mild soap and a damp cloth. No abrasives, which cut the coating and let corrosion start underneath.
Brass and copper develop a patina that many fixtures are designed to have. Mild soap preserves it; polish removes it and starts a maintenance cycle you cannot stop. Decide which look you want before you start.
Oil-rubbed and antiqued finishes are surface treatments that scrub off. Damp cloth only, no polish, no abrasive.
Stainless steel should be wiped with the grain. Chloride bleach pits stainless, so keep bleach-based cleaners away from it entirely.
Plastic and composite housings take mild soap. Solvents craze plastic and make it brittle. Sun-faded plastic cleans but does not restore.
Glass lenses take glass cleaner applied to a cloth. Frosted and seeded glass needs a soft brush in the texture. Aged glass lenses are often brittle -- handle them like they are.
The same finish logic applies to outdoor metal in general, covered in cleaning patio furniture by material.
Height, and the ladder question
Do not clean an eave-mounted or second-story fixture from a ladder while holding a bucket. Two hands are needed for both jobs.
And the absolute version: never operate a pressure washer wand from a ladder for any reason. The recoil is a serious fall hazard.
If a fixture is beyond safe ground reach, either take it down when it is next relamped and clean it at ground level, or hire the height work out. Roof-line fixtures and soffit lighting are usually handled during a broader eave cleaning, described in cleaning soffits and fascia without water intrusion.
What cleaning will not fix
Corrosion inside the housing, a socket that is green or crusted, discoloured or brittle wiring, and a fixture that trips a breaker are all electrical problems. Clean them and the underlying fault remains.
A lens that fogs from inside after cleaning has a failed gasket letting moisture in. New gaskets are often available; otherwise it is a replacement.
Chalky, oxidized paint that leaves powder on the cloth means the finish has broken down. Cleaning removes the loose powder but does not restore the coating.
FAQ
Can you spray outdoor light fixtures with a hose?
No. Exterior fixtures are gasketed against rain falling downward, not against water driven sideways under pressure. A hose or pressure washer stream gets past aging gaskets into the housing, where it corrodes the socket and terminals and can kill electronics or trip the circuit later.
How do you clean an outdoor light fixture?
Cut power at the breaker and confirm the light is dead, let it cool, brush out insects and cobwebs dry, remove and hand-wash the lens with mild soap, wipe the housing with a damp cloth, dry everything completely, reassemble, and restore power. No spraying at any stage.
Do I need to turn off the breaker to clean a porch light?
Yes. Switching it off at the wall is not enough, because a fault, a sensor, or a mislabeled switch can leave the fixture live. Turn off the breaker, verify the light will not come on, and only then open the fixture or introduce any moisture.
What is the best cleaner for outdoor light fixtures?
Mild dish soap in warm water for almost every finish, applied on a damp cloth rather than sprayed. Glass cleaner on a cloth for clear lenses. Avoid abrasives, solvents, and polishes unless you have decided you want to change the finish rather than preserve it.
Why is there water inside my light fixture?
Most likely a failed or compressed gasket letting rain or spray in, sometimes made worse by a previous washing. Cut power, open and dry the fixture completely, and replace the gasket if one is available. Persistent water intrusion with corroded terminals is an electrician's job.
The whole-house equivalent of this routine is covered by house cleaning services.
Exterior fixtures are the one part of a house wash that has to be handled by hand, and the breaker is the first step every time. If your lighting sits above safe ground reach, get a quote and we will fold it into the exterior plan.