Before you start cleaning anything old you find, you should check it does not have any historical value.
Objects that are incredibly old are very prone to damage, and this could be sustained through the cleaning process.
There is a website called the SHA which is a catalogue of old glass bottles. Unless it is very obviously recent, we recommend checking this website to ensure you have not stumbled across an archaeological discovery.
If nothing else, it is interesting to discover where and when your bottle was made.
Some old bottles have sold for thousands. The most expensive bottle ever bought was $200,000 and an old tequila bottle from Mexico.
Vinegar and Water
Find a large pot and pour in a decent splash of vinegar. Fill the pot up with water.
Fill your glass bottles with water too, to prevent them from floating to the surface. Add to the pot.
Heat the water for a couple of hours, but do not allow the water to boil as this could damage the glass. Once a couple of hours have elapsed, turn off the hob and allow the glass bottles to soak overnight in the pot.
The next morning, pour the water out of the glass bottles. Add a decent amount of salt to each bottle.
Add enough warm water to each bottle to create a salty slurry. The salt should not dissolve but it should be able to move easily around the bottle.
Cover the opening of the bottle with your finger and shake vigorously. Change the speed, direction, and angle of the bottle constantly to ensure the salty mixture covers all of the interior surface area.
The salt should scrub off any remaining dirt and debris from inside the bottle. When the glass looks clean, pour out the salt and rinse thoroughly.
Gently scrub the outside of the glass bottle with a plastic scrubber, a sponge or anything else that is non-abrasive. This is important as abrasive scourers will scratch the exterior surface of the glass bottles.
Vinegar and Dish Soap
Fill the glass bottles with vinegar. If they are dirty on the outside too, submerge the bottles in a large bowl of vinegar.
Soak them for at least an hour. Empty the vinegar from the bottles.
Cover the base of the bottle with ½ inch of salt. Add some dish detergent, enough to dampen the salt a little on top.
Cover the opening of the bottle with your thumb and shake well. This will agitate the salt inside the bottle and effectively scrub the interior. Add some more dish soap or a little water if the salt sticks to the base. Don’t add too much, as this will dull the abrasive action.
Shake the bottle for a minute or two. Empty the salt and rinse well with water. Repeat as necessary. Dry with a soft, lint-free cloth.
This method also works with uncooked rice and sand instead of the salt. It even works with a necklace chain and BB gun pellets!
Ice and Salt
Fill the glass with some ice cubes to about the halfway mark.
Add some salt and a little water to get the salt moving around the bottle.
Cover the opening of the bottle with your thumb and shake vigorously.
Empty the contents and rinse well with water.
Oxalic Acid
This is also called wood bleach and is sold in a powder. Mix in a 1:6 ratio with warm water. You can make this in a large batch and keep, sealed, for years.
When making the solution, it is vital to add the acid to the water and not the other way around. This is because the acid dust is very hazardous when inhaled. Store in plastic, as the acid eats through metal.
Wear safety goggles, a mask, and gloves when mixing.
Other Methods
Mix around 1 carton citric acid with 4 gallons water. Submerge bottles and allow to fill. Leave to sit for 2-3 days. Rinse and use.
Make a 10% solution of lye (also known as caustic soda) and water. Soak the bottles in the solution for a few minutes and then rinse.
Fill your glass bottles with warm water and crush a denture tablet in. Leave to sit for a few minutes and then rinse.
CLR is a calcium, lime, and rust remover. Mix in a 1:1 ratio with water and cover the top of the bottle with a gloved hand. Shake vigorously and then leave them to sit for about 2 minutes. Rinse well.
Bar Keepers Friend is a product designed to remove rust from glass. Sprinkle some of the powder inside and add a little water. Shake and leave to sit for a few minutes before rinsing.
Another method is to pour baking soda into the bottle. Add vinegar to about halfway up, cover the top and shake vigorously. Empty and rinse well. This is particularly effective for removing smells.
Rubbing alcohol, also known as isopropyl, is a particularly effective cleaner combined with rock salt. Use it in a 2:1 ratio of alcohol:salt. Cover and shake before rinsing. Wear gloves.
Labels
To get rid of labels there are a few different methods. The easiest way to do this is to soak the bottle in lukewarm water mixed with a little dish soap.
It’s important to ensure the water is not cold or hot as this could cause the glass to crack and shatter. Leave the bottles to soak overnight and scrape off the label residue.
Mix together some baking soda and vegetable oil to make a thick paste. Coat the label residue in this mixture and leave to sit for 2-4 hours. Scrub with a damp cloth to remove.
A more alternative method to try is coating the label residue with peanut butter. Rub it in with your fingers and leave to sit for a few minutes. Rubbing gently but firmly with your finger should remove most of the residue.