or
drawings
, or oil paintings, when cleaning and dusting them.
419. China and Glass
The best material for cleansing either porcelain or glass, is fuller's earth: but it must be beaten into a fine powder, and carefully cleared from all rough or hard particles, which might endanger the polish of the surface.
420. Porcelain
In cleaning porcelain, it must also be observed that some species require more care and attention than others, as every person must have observed that chinaware in common use frequently loses some of its colours.