Evaporust for gas tank cleaning

[wrndln]

I am new to using endoscopes to inspect things - however I have a couple colonoscopies, but I wasn't in control then! It seems like a good tool to have for inspecting hard to get to places. I see they are available for not much money on eBay. It appears the cheap endoscopes are connected to a USB port on a computer - most likely a laptop or hand held device - neither of which I current have. They seems simple enough to use. However, how do you inspect the inside of the gas tank through the relatively small gas filler hole. It seems difficult to manipulate the endoscope cable inside the tank. Would anyone that has used an endoscope device please explain how they are used.
Rusty Nelson