As glass collectors, we love it when our prized pieces are shimmering and clean. It shows off the properties of the glass and the original look, so, of course, we are eager to keep them that way or get them back to that state. With that, I see many collections that are dust and grime covered. I also see dirty pieces ending up at auction houses, which tells me that is how the collector kept them. I am often asked by both collectors and non-collectors if I clean my glass, and if I do, how. When I tell them yes, I am often met with a gasp, especially if the item spurring the question is of a particularly fragile nature. As a glass collector of many, many years, I am generally very comfortable with cleaning glass. For many, however, the thought of cleaning glass comes with concern and fear. Rightfully so, because there is always inherent risk each time you handle a glass item, or anything remotely fragile. I am here to offer my thoughts about evaluating whether or not to intervene and best practices if you do decide to take that step. This is by no means an article dictating what you should be doing or how you should be doing it, but rather a compilation of thoughts and tips based on my years of experience.
For me, there are four things to consider before cleaning your item. First, consideration needs to be given to value. A clean and damage-free item has far more value and collectability than a dirty and damaged one. Second, you should evaluate the rarity. Keep in mind that rarity does not directly correlate to value. Is the item so rare it could not be easily replaced, or could you easily find another? Often, it is somewhere in between, and you are still left with a possible difficult decision. The third matter you should evaluate is the level of fragility of the piece. Is it a super thin blown article with numerous applied details, or is it a very simple and thick piece without any applied details? Those two scenarios are at opposite ends of the spectrum. The fourth and last thing you should evaluate is whether or not the item has surface treatments, as cleaning can degrade these elements. Does it have gold or silver foil applied to the surface? If so, was the foil cased and is therefore protected? If it was not cased, the foil can often be easily removed by a simple scratch of your fingernail, let alone adding cleaning products and other abrasives to the mix. Was the surface iridized? Chemicals and abrasives can remove this treatment. Does the item have a cold-painted decoration or was the decoration fired on? The former is far more delicate than the latter. A thorough evaluation of all four is something I go through every time I have a piece I wish to clean.
All of these points come down to risk versus reward, and you need to decide for yourself how they connect with your item. Also consider whether or not the item is insured. Even if insured, I caution you about being cavalier with your precious glass articles. The money you receive from the insurance company will not bring back a singular item and may not allow you to find another otherwise rare one. In my opinion, collectors are merely the current custodians of these items, and we must do everything in our power to preserve them. Additionally, and this should go without saying but I will say it anyways, if the item has the original label do not submerge it and be careful when washing around it.
Once you have decided to clean the item, now you must determine the best way to do so. I will offer general tips and then techniques ranging from least harsh to most harsh. As for general tips, always use a plastic wash basin if you plan on submerging anything, as it reduces the chance your item will bang against the hard surface of your sink. Use warm water, not scalding. Jumps in temperature, in either direction, can cause your piece to crack or shatter. Use a gentle detergent at first, such as liquid dish soap. Slow your movements when washing an item to reduce the likelihood the piece slips out of your hands. As obvious as it sounds, it is worth saying here that warm soapy water and glass result in a very slippery situation. This is another reason to use a plastic basin, because if the piece does slip out of your hands it will hit something a bit more forgiving. I also recommend rinsing the article over a separate wash basin in case it slips out of your hands in this last step. Do not submerge very fragile and thin-blown articles, as they will float around in your basin, possibly causing damage. Use a soft sponge to clean the surface, not something abrasive like steel wool which will result in fine surface scratches that are permanent. When drying your article, set it on the counter with a towel down and pat it dry when it is stationary. Do not hold a large or heavy article with a towel in your hands, as it can easily fall and get damaged. If you have a vase with a narrow opening and you wish to reduce the likelihood of water spots forming on the interior, first dry it as best you can with a towel, and then rinse with rubbing alcohol. Discard the bulk of the rubbing alcohol in the sink. If the piece allows and you are readily able, turn it upside down to let the remaining rubbing alcohol run off freely. Water will leave spotting due to the minerals present, but rubbing alcohol will not. These are good general tips and I utilize them every single time.
As I mentioned above, start cleaning with warm soapy water. That will remove much of the general grime. If the piece allows you to submerge and soak it, do so for an hour and then come back and gently scrub with the sponge. Repeat if necessary. Sometimes decades of grime does not come off easily. If the article has fine grooves, use a toothbrush or wooden toothpick to clean inside them. You can also use glass cleaner on the exterior surface. I prefer the foaming kind. Personally, I like using warm soapy water first because I feel it gets more debris and grime off than glass cleaner does the first time. For touchups down the road, glass cleaner is a good option. Additionally, there are “extra strength” dish soap options, often in a spray bottle, that can be effective in removing grime and spots, especially if the item has been sitting in a case or cabinet for an extended period.
If I am cleaning a thin-blown vase, I do not submerge it. Instead, I place a kitchen towel down on the countertop, then I place the object on top of that so no glass touches a hard surface. I then start cleaning the exterior with warm soapy water using either a soft sponge or cloth of some kind. If the item is thick and without applied details or surface finishes, I am comfortable submerging and soaking it in soapy water. Use the harsher side of the sponge to remove any robust debris on the inside, if you are able to reach it. If the article, either thin and delicate or thick and sturdy, has interior water staining, I address that outside of the wash basin. I go back to the countertop with a towel down and add my cleaning chemicals to the vase. Always start with warm soapy water and a brush of some sort—you decide which is appropriate for your particular article. Water staining, often referred to as mineral deposits or build-up, is generally permanent, but I feel it is worth a try to lighten it. Into your soapy water add baking soda. This will act as a very gentle abrasive paired with your brush. Gently scrub, let it sit, and repeat these steps many times. If the opening or neck of the vase is too narrow for a brush, add dry rice to the soapy water and baking soda mixture and swirl your vase repeatedly. Let it sit and soak, then come back and swirl it more. Repeat these steps many times. The dry rice acts as an abrasive in lieu of a brush.
If adding the baking soda does not work, you can try chemicals such as Lime Away or CLR. Add a healthy amount with warm water to your vase, scrub with a brush, let it soak, and repeat as necessary. If the neck is too narrow, add rice as mentioned above and swirl. I have not had much luck using these chemicals, but it is still something I try on occasion. You can also try coffee pot or espresso machine cleaning chemicals that are intended to remove water scaling. The last and seemingly most harsh way to attempt to clean glass is a method I, personally, have not used but I have known people to have some results. Many of you may have heard of car headlamp defogging kits. These chemicals, paired with a gentle brush on a Dremel, or similar tool, can possibly remove mineral deposits. I will add that this method is concerning for me, as I am worried about damaging the original glass surface. I also worry about the heat created from the high RPM spinning brush causing a crack. I would rather see water staining than marks left from going too far with this approach. There are videos circulating online that discuss this technique more in depth, so I recommend reviewing those. I also recommend trying this method on an inexpensive piece first and looking back at it a few months later to see if it actually worked and if the original surface was damaged in any way. Lastly, keep in mind that the chemical composition of glass varies from company to company and not all will react the same way to each cleaning method.
After you have cleaned your glass, or decided not to, you should keep anything that is remotely difficult to clean behind glass in a case so it does not continue to get soiled. With open concept homes today, kitchen oils and grime seem to permeate through large areas of the home, and this type of soiling is difficult to remove if left on the surface for an extended period of time. For me, on surface tops such as coffee and side tables, sideboards, and dining tables, I only display pieces that are easily cleaned. When I see living room displays with glass on open shelving, I cringe at the thought of having to clean all of that regularly. I cringe even more when the open shelving is packed with delicate and difficult to clean items. While I understand the desire to display your collection, that is not a practical way when you overlay beauty, time, and preservation. As I have outlined here, there are many things to consider when wanting to clean a glass article, and then there are many avenues in which to proceed. The decision is ultimately yours and everyone will have a differing opinion in any given scenario. I encourage you to give careful consideration to the risks and rewards.