C-l-e-a-n, clean, verb active, to make bright, to scour. W-i-n, win, d-e-r, der, winder, a casement. When the boy knows this out of the book, he goes and does it.
Source: (Mr Squeers) Nicholas Nickleby, Ch. 8
-- Charles Dickens, (Feb 7 1812-1870), English novelist, dramatist; He was one of most prolific and popular English novelists, e.g., A Christmas Carol, 1843 & Tale of Two Cities, 1859.