Cleaning Stained or Dirty Pottery and China
Obviously, when cleaning pottery and china, you want to start with the simplest method first. There’s no need to dunk your Roseville vase in peroxide, if a simple soap and water solution will do the trick. So start with the easiest, lest damaging and work your way up from there. (Remember, there is always a risk to the pottery and china, so use the Guinea pig rule!)
Pottery and china accumulate more than dust over the years: oil from our hands, smoke from a fireplace, grease from a cooking stove. All of this builds up over the years, combines with dirt and dust and forms stains on the surface of the pottery, and staining in any cracks in the pottery’s finish (the effect known as crazing). This does not wash off with a simple swipe of the cleaning rag, but a lot of it can be soaked off. If soaking doesn’t work, then we can move on to more stringent methods like peroxide.
The Guinea Pig Rule:
Now here is a disclaimer and warning. I have not personally tried all of these methods (I will note the ones I have), so I cannot vouch for the success rate of some of them. Also, pottery and china are delicate things, and there is no guarantee that vigorous cleaning won’t fade the color or damage the finish. Before you dip great great grandmother’s favorite china cup in a 40% peroxide, try it out on an inexpensive, non-sentimental piece first and assess the results, then if you’re satisfied with how it turned out, you can move on to the more important pieces. This is the guinea pig rule – always try it out on a throw-away piece first before using it on your good china or pottery!
For Dirt, Stains and Caked on Grime
Soap and Water Soak
1. Clean the pottery with warm water and soap. I find the original Dawn liquid soap works best. Avoid soaps with scents and additives. Run a sink full of warm, soapy water and with a soft wash cloth, clean the pottery. It’s ok to put some elbow grease into it, but don’t use anything other than a wash cloth, as other materials such as a loofa or scrub brush could scratch the finish.
2. If simple cleaning doesn’t remove the dirt and staining, then draw up soapy water (again using Dawn) in a tub large enough to submerse the pottery in. A RubberMaid tub with a lid works well, but any bucket or plastic tub deep enough will do. Don’t skimp on the soap, use a fairly high concentration of soap to water. Submerge the pottery in the soapy water, making sure it is completely covered (you can also soak multiple items at a time, as long as the items are not touching). Place the lid on top and move the container to an out of the way spot in your kitchen. Let the pottery soak undisturbed for two weeks. After two weeks, remove the pottery from the tub and discard the water. Using warm soapy water and a washcloth, gently wipe down the pottery and see how much of the grim comes off. If there is still a significant amount of staining and grim left, draw up another tub of soapy water and soak the pottery for another two weeks.
3. If soaking the pottery in a soap and water solution doesn’t remove enough of the stain, you may need to move on to more aggressive methods. The guinea pig rule is especially important here, as there is always a risk to how pottery or china will react to a chemical! Also, remember NEVER use chlorine bleach products on your pottery or china, as it will destroy them!
1. Mix 2 cups of ammonia with 2 gallons of water and soak the pottery in the solution for not more than 24 hours. Remove from the solution and wash with soap and water. Pat dry.
**Remember to handle the ammonia carefully, wear gloves to protect your skin and don’t breath in the fumes.
40% Peroxide Soak method
40% or #40 Peroxide can be purchased at a beauty supply store, such as Sally, and is much stronger than the normal hydrogen peroxide you buy at your local CVS. When dealing with peroxide, always protect your hands and do not get any on your skin, as it can burn and cause blistering. I have read that peroxide will not harm items with gold or gilt decoration, but I would definitely test this out on a guinea pig before trying it on a valuable piece!
1. Pour the peroxide into a plastic container, if you have a dark container this is better than a clear one, as light can cause the peroxide to break down faster, and a dark container keeps out more light. Do not dilute the peroxide! For a large container, you will probably need 3 to 4 large 32 oz. bottles.
2. Submerge your pottery into the peroxide, making sure it is completely covered (you can also soak multiple items at a time, as long as the items are not touching). Put the lid on the container and store in a dark, cool part of the house. Let it sit for 2 to 4 weeks, depending on the severity of the stain or discoloration.
3. After 4 weeks, remove the item from the peroxide and assess the progress. If the stain is not gone, re-submerge the item and leave for another 4 weeks. Also, check your peroxide at this time, as peroxide loses strength over time and it may need replacing. You will know when to replace the peroxide because it tends to get discolored and starts to have an odor.
4. People have reported having to soak items up to 4 or 5 months, but I would check on the item every 4 weeks and assess whether the peroxide needs changing. If the stains on your pottery appear to be getting lighter, then by all means, continue soaking. If, however, you are not seeing any progress after 8 weeks, you may want to reevaluate if the piece is worth continuing with.
5. After you are finished soaking your pottery, be sure to wash it well in soapy water to remove any traces of peroxide. Pat dry.
40% Peroxide Wrap method
For more delicate items, or for items where the staining is in one spot and not over the entire piece, you might want to try the Wrap method instead of soaking your item. For this method, wrap the item in clean, white cloths that have been soaked in 40% peroxide, only putting the wet cloths on the spots that need whitening. Place the item in a large trash bag and seal it. The cloths will need re-wetting every few days, as they dry out.
For Mineral Deposits
Mineral deposits such as lime and calcium and rust can be surprisingly resistant to the normal cleaning procedures.
1. First start by cleaning the item well with warm soapy water. Soapy water will not remove mineral deposits, but it does get any excess dirt and grime out of the way, which can just complicate the cleaning process.
2. Soak the item in full strength, white vinegar. Do not dilute! For items like a bowl or cup, if the deposits are at the bottom, simply fill it up with vinegar and let sit. If it is some other items, or the deposits are on the outside, pour the vinegar into a plastic bucket or bin and submerge the item.
3. Items with heavy deposits may have to soak for several days. Each day, rub the problem areas with a clean, white cloth to loosen the deposits and continue soaking until all deposits are gone. Because vinegar evaporates, you will have to add fresh vinegar regularly.
4. If the vinegar does not remove the deposits, there is another method I read about, but am unsure about how safe it is to use on pottery and china. Be sure to try it out on a guinea pig first! If the vinegar is not removing the deposits, dissolve a denture cleaner tablet in distilled water and soak your item for several hours before removing and washing with warm soapy water. Pat dry.
Removing pencil marks, silver or black rub lines
1. First start by cleaning the item well with warm soapy water to wash away any excess dirt and grime. While you are washing your item, scrub at the rub marks with a clean, white cloth. Sometimes this is all it takes to remove the lines.
2. If the lines won’t come off with a simple cleaning, pat the item completely dry and rub over the lines with a #2 pencil eraser. Start with light pressure, and increase pressure as necessary (don’t scrub so hard you damage the finish, however).
If there are still lines and marks that won’t come off, there are two other methods I read about that you can try. I haven’t attempted either of these myself, so try them out on a guinea pig first!
3. Try using a small amount of Barkeeper’s Friend on a clean, white cloth with some warm water. Barkeeper’s Friend comes in two forms, powder and a soft paste. The product is somewhat abrasive, so don’t over scrub, or you may scratch your pottery. Apply and scrub only the area with the pencil or black lines.
4. Try using a small amount of metal polish on a clean, white cloth. Again, metal polish is slightly abrasive, so be sure to assess your pottery as you scrub and make sure you are not scratching the finish.