A common occurrence associated with esophageal stricture is food impaction of "foreign body" that interferes with swallowing and becomes very uncomfortable for the patient. Usually these foreign bodies are removed during flexible endoscopy. 
However, if the impaction is not easily removed by this method or if the patient is experiencing respiratory distress general anesthesia and surgical removal via rigid scope is necessary.
After removal of foreign body the patients return to have the stricture dilated. This is not done at time of removal due to trauma that occurs from the foreign body. Foreign bodies that do not become lodged in the esophagus or small intestine are passed through the GI tract the same as food.
From: Endoscopy: "An Insiders Look" by Krista M. Stayton, RN. Used with permission.
This dime was discovered at the base of the cecum during a colonoscopy being performed as a follow up for history of colon polyps. The patient was elderly and was not aware of swallowing the coin. X-ray performed two weeks after this exam was normal. No evidence of a coin was seen.
From: Endoscopy: "An Insiders Look" by Krista M. Stayton, RN. Used with permission.
Often, foreign bodies are pieces of a bridge or dental devices that are swallowed accidentally and sometimes unknowingly. 
The following patient presented with persistent signs and symptoms of small bowel disease such as diarrhea, epigastric pain and nausea for several months. Upon endoscopic examination a foreign metal object was found imbedded in the duodenum. It was thought to be part of her dental bridge and most likely the cause of her symptoms. During removal, the object broke in two and this piece was then retrieved from the esophagus.
Source: Endoscopy: An Insiders Look
by Krista M. Stayton