The phrase "accidentally discarded" is correct and usable in written English.
It can be used when referring to something that was unintentionally thrown away or removed.
Example: "I realized that I had accidentally discarded the important document while cleaning my desk."
Alternatives: "inadvertently thrown away" or "unintentionally disposed of".
Cheek accidentally discarded the heart six.
That means, the Web site says, you must "watch your mail, to make sure yours isn't accidentally discarded".
[Staff attorney] Gfactor found a story about a vial of radium accidentally discarded by a hospital; it was recovered after authorities allowed 500 pigs to graze the dump, then ran each animal by an improvised Geiger counter.
When I was informed by the Archives there were documents missing, I immediately returned everything I had, except for a few documents that apparently I had accidentally discarded". Mr. Berger is the subject of a Justice Department criminal investigation, not the target of one.
The fire was determined to have been caused by a burning cigarette accidentally discarded in a plastic trash can, which melted and then burst into flames.
Being an amateur myself, I picked up some slimy garbage in hopes of finding something edible, and accidentally discarded it in a fellow diver's general direction.
Do not pull them away or you may accidentally discard some of the artichoke meat.
By selecting two doses (instead of one), the study decreased its chances of accidentally discarding a dose that would ultimately be successful.
They list dozens of species whose well-being is threatened by overfishing; fish whose harvesting threatens species that are accidentally caught and discarded; and fish that contain dangerous levels of mercury, PCB's and pesticides.
Notions of identity and selfhood - what Richard Sennett, in The Fall of Public Man, calls the "involuntary disclosure of character in public" and "isolation in the midst of visibility to others" - are hilariously, deliberately and accidentally investigated and discarded in frame after abundant frame.
– Cans in all stages: larval (a can, entirely drained and lightly crushed), pupal (a can with about 300ml of flat warm beer still weighing heavy in it) and fly (the rare gem: a full, entirely unopened can, discarded accidentally among a wash of other, flatter tins) (this can is returned carefully to the fridge).
