In 1984 Orwell uses symbols, motifs, imagery, and objective correlatives to amplify his themes of freedom vs. control, destruction of language, and mutability of the past.
Regarding the theme of freedom vs. control, Orwell uses the Golden Country to represent freedom and Room 101 for control. He uses the flat above the antique shop to represent both (first freedom, then control). He uses all the telescreens, ministries (of Love, Truth, Peace, Plenty), and Big Brother as monolithic symbols of secrecy, surveillance, and government control. They are omnipresent. He juxtaposes these with Winston's little nook where he writes in his journal. It is the only place of safety in the entire book.
The ultimate form of government control is the use of torture, developed in the final chapters. He uses the objective correlative of Winson's ulcer to represent his sense of rebellion from which O'Brien will cure. The most obvious symbols of control are the rats and bugs, anthropomorphic imagery that propagate fear. Other symbols related to torture are the boot, bombs, war, sirens, rations, etc... Winston becomes a symbol himself by the end, an unperson, a shadow.
Regarding destruction of language, Orwell uses Winston's job at the Ministry of Truth (the ash bin) and the Newspeak lexicon (dictionaries) to show how language is limited as a means of control. All morphed words are but symbolic abstractions that the government use to replace humanistic and personalized language. All banners, slogans, news flashes, films, rallies, and Goldstein's book are symbols of censorship and propaganda that instill fear in the users of language.
Regarding mutability of the past, the coral in the glass is symbolic of the once natural beauty that is now encased in a vacuum. Winston is desperately looking for symbols of his past, his mother, who he once was, a keepsake, his memory. He cannot find much of anything, only prostitutes, dead ends, pain, suffering. Orwell chooses not to use symbols to trigger Winston's emotional past. In this regard, Winston is so bombarded by symbols of the state that he can no longer identify personal ones. Is this not the destruction of language: when memories, family, love no longer have symbolic and personal meaning?