We have over 350 individual ceramic or glass objects at Knole. We have items ranging from 18th century wine bottles to Sevres and Royal Worcester porcelain to Imari plates. During the winter clean is every piece is cleaned and inspected for any change in its condition. Pieces closest to the visitor route are also dusted at intervals in the open season.
During the last week of opening we began wet cleaning the ceramics in Lady Betty’s China Closet as a part of our ‘putting the house to bed’ demonstration event.
Depending on the condition and the decorative surface of a ceramic object, to remove dust we use either a hog’s hair brush or a softer pony hair brush. The extremely high levels of relative humidity at Knole can cause dust to stick to the surface of the ceramics. This can mean dusting with a brush alone does not remove all the dust particles.
To remove the stuck on dust we wet clean the ceramics every other year. We do this using a piece of cotton wool or cotton bud, dipped into water containing a small amount of conservation grade detergent. We go over the ceramics a second time, again with cotton wool lightly damp, but with just plain water to remove any traces of detergent. We then carefully dry the piece with a paper towel.
Any piece that is cracked, chipped or has a previous repair can not be wet cleaned as the risk of water getting behind the glaze could cause further damage. Ceramics with decorative gilt are only cleaned with a pony hair brush as water could remove the gilt. The pieces are then wrapped in acid free tissue paper to keep them clean until we open again.
Sarah, Melinda Lucy and Emily