How to clean mirrors without streaks or black edges

Step by step: how to clean mirrors without streaks or black edges

1. 1

   Dust the mirror first

   Wipe the whole mirror with a dry microfiber cloth to remove dust and lint. Dust smeared with water turns into the gray haze that makes people think they need a stronger cleaner.

2. 2

   Spot treat toothpaste and hairspray

   Dab dried toothpaste flecks and hairspray mist with a cotton pad dampened in warm water and hold it there for 20 to 30 seconds to soften them. Lift dried-on blobs with the edge of a plastic card rather than scrubbing, which spreads them into a smear.

3. 3

   Dampen your cloth, not the mirror

   Dip one microfiber cloth in warm water and wring it out until it is only damp. If you need a cleaner, spray it onto the cloth. Spraying the mirror directly sends drips down to the bottom edge, where the reflective backing is exposed.

4. 4

   Wipe in an S pattern from top to bottom

   Start in a top corner and wipe across, then down a little and back, in a continuous S shape to the bottom. This pulls the dirt down and off instead of pushing it around in circles. Refold the cloth to a clean side as it gets dirty.

5. 5

   Buff dry right away

   Immediately go over the mirror with the second, dry cloth in the same S pattern. Streaks form when water or cleaner dries on its own, so do not let it air dry.

6. 6

   Dry the edges and joints

   Run the dry cloth along all four edges and any seams between mirror panels. If several mirrors meet on a wall, wipe along the joint, not across it, so liquid does not collect where the panels meet.

7. 7

   Check from an angle

   Look at the mirror from the side with a light on: streaks and lint show up at an angle that you miss straight on. Buff any spots with the dry cloth.

Why shouldn’t you spray cleaner directly on a mirror?

Because liquid runs to the edges and attacks the silver layer on the back, causing dark spots called black edge. Mirror makers say to put cleaner on the cloth instead.

A National Glass Association technical paper on cleaning mirrors says to avoid getting mirror edges wet with any liquid, that wet edges can cause the damage known as black edge, and that edges which do get wet should be dried immediately. It names clean, warm water with a soft, lint-free cloth as the very best and safest cleaner, with the cloth wrung out before wiping and the mirror dried straight away.

American Specialties, a mirror maker, gives the same instruction for its mirrors: never spray cleaner on the mirror, apply it to a soft cloth so it cannot puddle at the edge and attack the backing.

What is the best cleaner for mirrors?

Warm water and a good microfiber cloth handle most mirrors. When you need more, use a little ammonia-free glass cleaner on the cloth, and skip anything acidic, alkaline or abrasive.

Bobrick’s mirror care bulletin says not to use mirror cleaning products containing ammonia, vinegar, acid or alkali, never to hose a mirror down, and to make sure all joints and edges are dry after cleaning. For LED and backlit mirrors it adds that liquid sprayed on the surface can wick between the layers at the edge.

Can you fix black spots on the edge of a mirror?

No. Black edge and dark spots are damage to the silver backing, not dirt, so no cleaner will remove them. You can only stop them from spreading.

• Keep the edges dry: buff them after every clean and after steamy showers.
• Improve bathroom ventilation, because constant humidity also attacks the backing.
• Small spots near the edge can be hidden with a frame or trim; larger ones mean the mirror needs replacing.
• For shower doors and other bathroom glass, use our guide to cleaning shower glass, which can take stronger cleaners than a mirror.

Mistakes to avoid

• Spraying glass cleaner straight onto the mirror so it drips into the bottom edge.
• Using paper towels, which leave lint and can hold grit.
• Wiping in circles, which just moves the dirt around.
• Letting the mirror air dry and leaving water streaks.
• Cleaning with a cloth washed with fabric softener, which leaves a waxy smear.