How to clean cloudy glasses: foolproof tips from an expert!


Polishing the inside of a crystal glass with cerium oxide

Cloudy glasses are due to either hard water deposits or etching from harsh dish detergents. Most home remedies on the internet are totally ineffective. Learn from a glass professional how to remove cloudiness from glass or crystal.

Etched glass at Govinda's Restauran... x
Etched glass at Govinda's Restaurant, Tucson

The best way to clean cloudy glasses is either to use a professional hard-water stain remover like Water Spot Remover from CRL or to polish with cerium oxide. Most other, highly promoted, substances like toothpaste, household vinegar, lemon juice, eggshells, baking soda, borax, acetone, WD-40, CLR, and others are ineffective.

The first step is to determine the cause of the cloudiness – is it hard water or etching by detergents?

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Before revealing the answer to all your cloudy glass questions, it is interesting to discuss the bewildering array of ideas for removing cloudiness in glassware and crystal found on the internet. These ideas can be divided into dissolving methods and abrasive methods.

Dissolving methods

There is scientific justification for some of these liquids because hard water stains are mostly composed of carbonates (calcium & magnesium) that are dissolved by acids like vinegar (acetic acid) and lemon juice (citric acid).

  • Vinegar
  • Lemon juice
  • Ammonia
  • Rubbing Alcohol
  • Hydrogen peroxide
  • WD-40
  • Commercial products like CLR (Calcium/Lime/Rust)
  • Nail polish remover (acetone)

Some ideas make sense in theory but ……

Note that vinegar may be effective on minor hard water stains because acetic acid dissolves calcium carbonate. The problem is that household vinegar is only 5% acetic acid and is not strong enough for tough stains. If you would rather use vinegar instead of our #1 recommendation, then purchase the industrial strength variety (75% acetic acid) from Amazon. (Don’t forget to follow the safety instructions).

Products ineffective for hard water removal

Note that liquids other than acids have no chance of dissolving hard water deposits. So do not waste your time with acetone, alcohol, hydrogen peroxide, or ammonia – read on to find the guaranteed and proven methods.

Abrasive methods (grinding/polishing)

The idea behind the second category of home remedies is to use mechanical methods to remove the cloudiness. Either by removing a very small surface layer (by polishing) or by bombarding the surface with hard objects (rice/lead shot) to loosen up and dislodge the cloudy scale.

  • Baking soda (sodium bicarbonate) – pH 8.0 – hardness 2
  • Cream of tartar (tartaric acid) pH 3.00
  • Borax (sodium tetraborate) – pH 9.5 hardness 2 – 2.5
  • Fluoride toothpaste (with calcium carbonate – hardness 3)
  • Denture tablets (effervescent)
  • Any of the above solvents like vinegar together with:
  • Uncooked rice, peas, eggshells, lead shot.
  • Fine sandpaper (5000 to 10,000 grit) or steel wool
  • 3-m “Scotch-Brite” pads
  • Mr Clean “Magic Eraser”

Some methods make sense in theory but ……

Like everything else in life, there is some truth in even the most bizarre conspiracy theories. However, most of these abrasives (like the minerals in toothpaste) or the grains of baking soda are much too soft to be effective.

Also, used by amateurs, many abrasive methods can make the situation worse by scratching (especially easy to do with soft lead crystal).

Home abrasives & mechanical methods for glass cleaning

Ineffective abrasive methods purported to remove cloudiness – using products commonly available in the home. Note that some products, used in conjunction with solvents, (like crushed eggshells or dried rice swished around with vinegar) may be effective on minor hazing.


The truth about home glass cleaning remedies!


Traditionalists really love old-fashioned home remedies because they appeal to their frugal instincts and because they use products that are commonly available in the home (either under the kitchen sink or in the bathroom).

Streetlight effect - looking for keys

Using the wrong products, because they are available, is like searching for your keys in the wrong place (because light is available).

The unfortunate fact is that most do not work except on very minor hazing, many are a complete waste of time, some are counter-productive, and a few will cause damage.

The common frustration, as you try these methods, is that the glass appears to be miraculously restored to its original sparkle – only for the dreaded cloudiness to reappear as the moisture gradually evaporates.

If you would rather watch the post on YouTube – click the video below:


Step 1: Identify the cloudiness

The first, and most crucial step in cleaning glasses is to find out what’s causing the cloudiness.

Two main types of cloudiness affect crystal and glassware: hard water deposits and haziness caused by the etching of crystal with strong detergents. It is vital to distinguish between them in order to choose the best treatment.

Cloudiness caused by hard water deposits:

Most domestic water supplies contained dissolved mineral salts unless you have a well-calibrated water-softening system.

Hard water stains caused by calcium carbonate

Hard water stains are whitish surface deposits of calcium carbonate and other salts caused by the evaporation of tap water. The staining often shows a pattern of rings marking the decreasing levels of the evaporating water.

How to remove hard water stains

Don’t waste time with home remedies – use professional water spot remover from CRL for quick and easy removal of hard water deposits

Making sure to use rubber gloves and protective face wear, carefully pour CRL Water Spot Remover into the glass, vase, or bowl that has hard water stains. (For most stains you can use a 50-50 dilution with tap water, but increase to full strength for serious deposits.)

Stir or agitate the liquid with a soft brush and observe the hard water scale miraculously fall away from the surface of the glass. Do not allow the CRL liquid to sit in the crystal – you may form a ring – pour it out of the glass once you see that it has worked and immediately rinse thoroughly with clean water. (save the used CRL – it is strong and can be used several times).

!!CAUTION!! (the small print)
CRL WATER SPOT REMOVER IS VERY DANGEROUS. FOLLOW THE MANUFACTURER’S INSTRUCTIONS. ARTISTRY in GLASS CAN NOT BE RESPONSIBLE FOR ACCIDENTS OR INJURIES INCURRED AS A RESULT OF USING CRL WATER SPOT REMOVER

Our recommendation for the removal of hard water stains

Precautions before using CRL

Never use CRL on decorated (enameled, painted, or gilded) glass or crystal without careful testing. Always test CRL on a Q-tip on an inconspicuous part of the crystal (the base) before using.

Libbey glass with hard water stains and after cleaning

Before and after views of glass treated with CRL Water Spot Remover. If the cloudiness does not disappear then your crystal must have suffered from etching (see below).

Haziness caused by etching of crystal

A quite different type of cloudiness is caused by strong detergents or phosphates attacking the surface of the crystal. Etching of this type is not a surface deposit but is a change to the atomic structure and it is most common in delicate lead crystal like Waterford, Lalique, Bacarrat, and Swarovski. Jump to this section for tips on the washing and care of fine crystal.

Case study – cloudy lead crystal with scratches

When interviewed, the customer revealed that she had regularly washed these glasses in the dishwasher. On examination, the hazy cloudiness looked like the product of etching by the phosphates or strong chemicals in dishwasher detergents.

Foggy and scratched crystal glass

Swarovski crystal whiskey glass with hazing. The owner tried to remove the cloudiness but used an abrasive 3M Scotch-Brite scouring pad and made the glass worse by creating very fine scratches.

The correct approach to remove fine scratches and dishwasher stains

Polishing the inside of a crystal glass with cerium oxide

A simple, effective, and foolproof method of removing haze and fine scratches is to polish with cerium oxide on a foam pad. Cerium oxide is a fine abrasive specially formulated for glass.

Crystal glass with stains removed by polishing

Clouding is removed and the lead crystal sparkles like new. Note that cerium oxide will remove fine scratches but not ones deep enough to be felt with a fingernail.

Our favorite products for polishing cloudy glass are those shown below (available on Amazon). There is a wide variety of pads so use your common sense to choose large or smaller ones depending on whether you are fixing small shot glasses or large vases.

Foam pads for use with cerium oxide polish

Notes on the dangers of lead crystal

Because of the dangers of poisoning, lead is not used in the manufacture of fine crystal these days. For a full explanation of the properties of lead crystal and the dangers to pregnant women – be sure to check out this extremely informative post.


Tips for the washing and care of stemware

  • Remove rings & jewelry before washing crystal
  • Wash stemware in warm soapy water – never in the dishwasher
  • Place a washcloth in the bottom of the sink
  • Hold crystal by the bowl – never the stem
  • Before using, make sure the glass is free from detergent
  • Never pour very hot liquid into crystal
  • Check for water spots before storing your crystal
  • Remove water spots with a mixture of vinegar & water
  • Do not store crystal stemware resting on its rim
  • Never store one crystal glass inside another one

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John

I was an exploration geologist and University Professor working in Botswana, Zambia, Brazil, Saudi Arabia, the Netherlands, and other countries before opening Artistry in Glass in 1986. In my more than 30 years of experience, I have brought my technical abilities as a scientist to the trade of glasswork. In this time I have become an industry expert in glass and glass-related skills. Watch out for special insider tips developed from my detailed knowledge of the glass business.

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