cleaning a fuel tank

I have a 1969 with the originial fuel tank. I believe that I have some trash in the tank. You can see small black dots on the sides of the tank. I started having a problem with the carb flooding out when the car is at idle. I had the carb rebuilt a few months ago. The car has been running good until about a week ago. My mechanic suggested that maybe some trash has got into a carb jet needle and is causing the flooding. He suggested cleaning  the tank out and replace the fuel filter. Any suggestions on how to best clean the tank? I was thinking of pumping out all the gas and then cleaning the tank with some rags and wipe the dirt and junk out.

Eastwood has some great how to videos on their site. I think you need to drop the tank to do it right......