Disclosed are methods for performing endoscopy comprising directing a distal end of an endoscope to proximity of a portion of a surface of a bodily cavity； and directing a liquid-gas stream at a portion of the surface of the bodily cavity. Disclosed are also devices useful in endoscopy, comprising: an elongated body having a proximal end and a distal end； a nozzle at the distal end； a gas channel configured for conveying a gas from the proximal end to the nozzle； and a liquid channel configured for conveying a liquid from the proximal end to the nozzle, wherein the nozzle is configured to generate a liquid-gas stream directed in a specified direction from a gas conveyed by the gas channel and a liquid conveyed by the liquid channel.
