I have a old Coleman gasoline only lantern model 202 an there is rust in the tank of the lantern can I use it like that. if not how can I clean the rust out?

I would suggest not to. Lanterns that burn liquid gas have a very small needle that the gas vapors must pass through. It can clog very easily, especially if there is any kind of debris in the tank. While it may work for you, I would not want it to let you down and stop working at just the wrong time. Like halfway to the outhouse.