Cleaning Antique Bottles & Glass
Many have asked us for information on cleaning dirt, rust stains, and other material from glass and bottles. Here are some general guidelines based on years of experience:
Dirt and other stubborn material on the glass surface and inside the bottle: Soaking in warm (room temperature) water with dishwashing detergent is a highly effective way to remove most dirt and stains. Always be careful not to place a glass object in water that is either much warmer or colder than the object itself. The sudden change in temperature may cause the glass to crack. Let the glass soak for several hours or preferably overnight. We have also heard of people using denture cleaning tablets or powders when soaking bottles with good results.
Mineral Deposits: Bottles, vases and other glass objects that have been used to hold flowers or were constantly filled with water can sometimes get a crusty white buildup on the glass surface that is difficult to remove. This buildup is caused by mineral deposits. There are certain types of bathroom/household cleaners that will remove lime scale and mineral deposits. Don’t confuse mineral deposits with etching, which is discussed below. Mineral deposits are often present along with staining of the glass.
Etching/Staining: White stains and cloudiness on glass is caused by the leaching or removal of certain components of the glass mixture over time. This often occurs on the inside of bottles that have contained a liquid or have been buried in the ground. These stains cannot be cleaned by conventional means, but must be left to a glass cleaning professional. A super fine polishing compound is typically used in a rock tumbling-type process to restore the glossy surface of the glass. The cost for this service typically ranges from $10 to $50, depending on the severity of the stain and the amount of work involved. Light removal of stain is an essential guideline; overcleaned glass look overcleaned, and it hurts its value.
Scratches and bruises: Minor scratches can be removed by a glass cleaning professional, but often you have little choice but to leave them alone.
Rust Stains: These stains are often left on dug bottles and can be difficult to remove. Scrub with a non-abrasive pad or gently scrape with a piece of copper, which wont scratch the glass. Dilute muriatic acid does a fantastic job of removing rust but must be handled with great caution: rubber gloves and eye protection are musts.
Dried Liquids/Paint/Etc. inside Bottles: Soak the object in dishwashing detergent and water as a first attempt. We have also had good luck by filling a bottle with paint stripper. Cork the bottle and leave it for 2-5 days.
Do This: Always use a non-abrasive pad for scrubbing. Copper wool pads are available at some grocery and hardware stores, and these will not scratch glass. Make sure that the copper pads are really copper and not just copper-colored or copper plated. Use soft bristled bottles brushes for cleaning the inside of bottles. Extra fine steel wool (OOOO) can be used with caution.
Don't Do This: Coarse steel wool and many household synthetic scouring pads can scratch glass. BBs, sometimes used to clean the inside of bottles, can also scratch glass.
Hydrofluoric Acid: This is an extremely dangerous acid and it is the only acid that reacts with glass. It was once popular for cleaning etching from bottles, but is not easily controlled and can instantly cause disastrous results. Unfortunately it will often ruin a glass object, not to mention burning a hole in your arm. We do not recommend using it.