Of American-English origin, apple polisher denotes a person who curries favour with a superior, and apple polishing means (an instance of) currying favour.

These nouns refer to the former practice of bringing a shiny apple as a gift to one’s teacher—and indeed they were first used in educational contexts.

The earliest instance of the figurative use of apple polisher that I have found is from the Chester Times (Chester, Pennsylvania) of Saturday 30^th November 1918, which reported that, during a meeting of the Association of Colleges and Preparatory Schools of the Middle States and Maryland, held at Princeton, New Jersey, President Nicholas Murray Butler (1862-1947), referring to the period before the war in his address on “Education After the War”, had said:

“We have been living in an era of reaction that has masqueraded as progress, and we have been witnessing energetic acts of destruction whose agents sang the songs and spoke the language of those who build. Part of what we have been living through and putting up with as best we could, has been due to a false psychology and part to a crude economics. The moral and spiritual values have been ground between the upper and the nether millstones of a psychology without a soul and an economics with no vision beyond material gain. A sense of humor or a flash of common sense, had either been present, might have saved us from being obliged to contemplate the ideal world made up of highly accomplished apple-polishers and pencil-sharpeners early trained in their engrossing tasks, and vocationally guided to be loyal and charitable to themselves alone.”

Likewise, the earliest instance of the figurative use of apple polishing that I have found is from the review by David Starr Jordan (1851-1931) of On the Campus: Addresses delivered at various times before university and college audiences, by Thomas Huston Macbride (1848-1934), President of the University of Iowa from 1914 to 1916—review published in the Los Angeles Times (Los Angeles, California) of Sunday 21^st February 1926:

Among the men chosen as college presidents in America, there are many varied types. The average president is a kind of honored outcast with whom no professor is willingly seen speaking, lest he be accused of “pulling the old man’s leg.” Conversation with pupils, in local academic slang, is known as “apple polishing” but no president I know of (and I was one for more than a third of a century) has had the nerve yet to inquire which is the apple and who contributes the polish.

The actual practice of bringing an apple to the teacher was mentioned in the School Page, edited that day by Adelphi College, of the Brooklyn Daily Eagle (Brooklyn, New York) of Wednesday 10^th March 1926; in Feminine Wiles Work Wonders in Winning Good Marks, Girl Says, Catherine Cleary wrote:

There is, of course, one aspect of college classes which while amusing is often an annoyance to the professors. This is the popular pastime known as bluffing. The majority try it with various degrees of success, depending somewhat upon the cleverness with which it is employed and the gullibility of the professor. Flirting, sidetracking them in discussions and apple-polishing are some of the methods used. The latter is a more or less sophisticated mode of emulating the teacher’s pet who brings her a rosy apple and spends much time in talking to her about anything under the sun, as long as he can hold her interest.

It is interesting to note that there also existed the practice of polishing apples displayed for sale; an early mention appeared in an article about “the trials and tribulations of the census enumerator”, published in the Scranton Tribune (Scranton, Pennsylvania) of Wednesday 13^th June 1900:

A writer in the New York Journal, who seems to be gathering material for a book while making the census canvass, expresses some of the experiences encountered by himself, and he undoubtedly speaks for thousands of his fellow enumerators […]:
“[…] I guess the funniest occupation of all is held by a boy who calls himself an ‘apple polisher.’ He puts the suspicious shine on the apples sold by a syndicate of Greek push-cart pedlers [sic].”

Booth’s, “the big store with little prices”, used to sell apple-polishing gloves, as attested by this advertisement published in The Hood River Glacier (Hood River, Oregon) on Thursday 19^th October 1905:

Gloves. We sell the kind that wear. Apple polishing gloves, 3 pair 25c; oiled canvas gloves, 25c; asbestos tanned working gloves, 50c; heavy calfskin gloves, 85 cts.

This practice was also mentioned in The Gazette Times (Pittsburgh, Pennsylvania) of Tuesday 18^th October 1910, in an article about the Land Show, an exhibition of “products of the soil” from all parts of the United States, which had opened the previous day in Duquesne Garden, Pittsburgh:

Maryland’s Display of Apples.
The first booth to the right, on the upper side of the hall, represents the state of Maryland, and is in charge of Prof. C. P. Close and Prof. Nicholas Schmidtz, horticulturist and agronomist respectively. It is largely built up of apples, of which Mr. Close, pointing with pride, said:
“You just say to the readers of The Gazette Times that we do not polish our apples any more than our Maryland ladies polish their faces. They are just as they came from the trees.”
Mr. Close smilingly backed away from any suggestion that his remark might imply that apple-polishing is done by some others.