“He pushed open this door, as he had been told to do, and found himself in a tiny room, which contained no furniture but a plain kitchen table, a rocking-chair, and an ordinary chair.”

Collier establishes a contradictory mood in the first line. Someone else has recommended the proprietor’s shop, indicating efficacy. Inside, however, the shop is tiny and plain.

“On one of the dirty buff-coloured walls were a couple of shelves, containing in all perhaps a dozen bottles and jars.” 

Not only is the shop plain, it is unkempt. It apparently employs no one and makes no concession to beauty or to maintenance. On the surface, these bottles are treated like the barest commodities, like ketchup bottles shoved to the back of a grocery shelf.

“‘Call it a cleaning fluid if you like,’ said the old man indifferently. ‘Lives need cleaning. Call it a spot-remover.’” 

Understatement is the lingua franca of the proprietor of the shop. He never just says what he sells, or why one would buy it. It is the only form of artistry he uses to present his wares, and it is brutally effective.