Roundhouse Objects Conservation - Oct. 30, 2012

October 30, 2012

Cleaning Ceramics

With the assessment of the roundhouse objects completed and approval from the curator to proceed the next step is to do the cleaning.  I have concentrated on ceramics in the first phase of cleaning.  In general the ceramics are part of the railway dining car sets that were broken or disfigured and then thrown away.  The cleaning is done in several steps as follows by using:

1. a stiff brush such as a smaller art painting brush to brush away the loose material,
2. a wooden pick with a sharp point such as a shish-kabob stick to dislodge dirt from crevices,
3. a tooth brush to dislodge any more stubborn material,
4. a soft cloth dipped in soapy, distilled water to wipe off stains, soil,
5. a second soft cloth to rinse with distilled water.

Conservation Tip:  Be very careful when cleaning to avoid any damage to the makers mark or a registration number often found on the bottom of ceramics such as cups, bowls or plates.  It is best to avoid these to ensure that they will remain readable.  This is also true for all historical objects with any identifying marks such as the owner's initials, signature, and so on which can be found in paper, cloth, leather, glass, and so on.  Any loss of readability is to be avoided since the marks often assist in determining dates, history of use, owner, and/or maker of an object.  The ceramics we cleaned had identifying marks which we left alone as shown in the photograph below.  The makers mark in this case was applied before it was glazed and fired so it is stable but the registration number was added later and is somewhat fragile.

Makers mark in the centre
Registration number in black ink below it

Photographs are taken of all objects before and after with a scale and a label to record the removal of material.  All work is done using gloves and on a base of plastic to control moisture.  The soap is the same one used to clean mouldy textiles - Orvus.  In all cases we were able to remove most of the soil and what looked like rust stains.  Some would not come off with minor amount of pressure so were left as is.  Below are photographs showing before and after with this type of cleaning.  Please note that only a small amount of material was removed in this example as found around the outside edge of the base and around the handle while some of the red marks also came off.

Ceramic cup before cleaning

Ceramic cup after cleaning with
soil bits removed shown on lower right

The following photograph shows three cups that were part of a package that came together.  It shows the tools and materials used to do the cleaning and they show what is an interesting progression of deterioration from the worst to the best.  The coloured band around the upper part of the cup is the best illustration of this - if you look closely at this band in the line up of cups at the top of the photograph you will see how the colour goes from almost completely faded on the left hand cup to bright, vibrant colours on the right.  This begs many questions in terms of the amount of time these objects spent exposed to the elements: whether they were exposed to more or less sun, the effects of soil on the coloured parts, and so on.    Was it exposure to sunlight that faded the colours or exposure to soil or a combination of both?