So portable generator tank spot rust

[LS short box]

I have a WEN 2017 7 hp portable generator. It was a retirement gift four years ago.
I started it when I got it and then ran it out of gas. It has sat for the last four years. No gas in the tank. Today I took a look at inside the gas tank and it has rust spots inside the tank. Washed out tank with gas. Petcock was filled with rust specks. Petcock has a filter.
Tomorrow it goes to the local car was to get a real cleaning.
Any other thoughts on cleaning or sealing the tank.