A single scratch can mar the entire appearance of a mirror. And unfortunately, these scratches can be difficult and expensive to repair. The only sure-fire way to repair a scratch flawlessly is to have it resilvered, which is a costly and often hard-to-find service. However, there are a few faster and cheaper fixes that won't yield perfect results but that might obscure the scratch enough that only you know about it.
Examine the mirror closely to see if you can tell how it is held together. Look for screws, clips or removable panels. Try to envision how you might disassemble the mirror. If the best way to take it apart isn't obvious, consider other repair methods first. You could break or damage the mirror if you try to take it apart improperly.
Carefully remove the mirror glass using the most appropriate tools for your mirror. You may need a screwdriver for removing screws, a claw hammer for removing nails or a putty knife to pry pieces apart. It is not necessary to take the entire frame or mirror assembly apart; you only need to remove enough parts to be able to safely remove the mirror glass from the frame. On many framed mirrors, you can do this by removing the back panel and taking the glass out from the back.
Use scissors to cut a piece of smooth aluminium foil that is just slightly bigger than the scratch. Do your best to get a piece that has not been wrinkled at all.
Smooth out the piece of foil as much as possible. If you started with a smooth piece, you may not have to do much but flatten out the edges. If necessary, use something flat like the edge of a butter knife to smooth it out. If you tear or wrinkle the piece, start over with a fresh piece of foil.
Find the panel of the mirror that is directly behind the mirror glass lay it face up on a flat surface. Carefully place the foil on the panel in the same place where the scratch on the glass is located.
Carefully set the mirror down on top of the back panel to see what it looks like with the foil behind the scratch. If the foil is slightly out of place and is not covering the entire scratched area, lift up the glass and carefully adjust the position of the foil. If the foil does not appear to improve the appearance of your mirror to your liking, you may want to consider another method.
Carefully lift the mirror glass and set it aside, making sure that you do not move the piece of foil.
Tear off four small pieces of clear tape and place them on the corners of the foil to stick it to the back panel.
Reassemble the mirror by reversing the process from step two.
Carefully examine the scratch. If any part of the scratch looks black, you will not be able to dramatically improve the appearance of the scratch using this technique. If you can see and feel the scratch but it appears as white or reflective, you may find success with this technique.
Wash the scratched area with a glass cleaner and buff it dry with a soft rag.
Lay the mirror flat on a working surface with the glass up.
Pump out a small amount of clear silicone caulk on a paper plate or scrap paper.
Dip a toothpick in the caulk and carefully fill in each scratch, using as little caulk as possible. Make sure every scratch is filled completely and try to minimise caulk build-up on the unscratched sections, but don't worry about wiping it up as you work. If your toothpick builds up a film and loses its fine point while you're working, switch to new toothpicks as needed.
Allow the caulk to dry and harden completely.
Use a razor blade tilted at about a 45 degree angle to the mirror's surface to carefully scrape away any excess silicone. Be sure to scrape in the direction of the scratches.
Clean the area again with glass cleaner and buff it dry with a soft cloth.
Look for glass and mirror specialists in your area. You can do this by searching online or by looking in your local phone book under "mirrors" or "glass repair."
Call each glass or mirror specialist to inquire whether or not they resilver mirrors and, if so, how much they charge. Write down prices as you go. It's important to shop around for a good deal because resilvering is often very expensive.
Take your mirror to the repair shop that offers the best price unless you feel as though another shop would do a better job. Make sure you point out all of the scratches when dropping it off.
Pick up your repaired mirror when it's ready.